| blob | 2fb327a3e28889faba605230cbc4783eb78d2186 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2018 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win". */
45 /* The type of functions taking a tree, and some additional data, and
46 returning an int. */
49 /* The PENDING_TEMPLATES is a TREE_LIST of templates whose
50 instantiations have been deferred, either because their definitions
51 were not yet available, or because we were putting off doing the work. */
55 };
70 /* Live only within one (recursive) call to tsubst_expr. We use
71 this to pass the statement expression node from the STMT_EXPR
72 to the EXPR_STMT that is its result. */
75 // -------------------------------------------------------------------------- //
76 // Local Specialization Stack
77 //
78 // Implementation of the RAII helper for creating new local
79 // specializations.
82 {
85 else
87 }
90 {
93 }
95 /* True if we've recursed into fn_type_unification too many times. */
99 {
100 tree tmpl;
101 tree args;
102 tree spec;
103 };
106 {
109 };
115 /* Contains canonical template parameter types. The vector is indexed by
116 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
117 TREE_LIST, whose TREE_VALUEs contain the canonical template
118 parameters of various types and levels. */
121 #define UNIFY_ALLOW_NONE 0
122 #define UNIFY_ALLOW_MORE_CV_QUAL 1
123 #define UNIFY_ALLOW_LESS_CV_QUAL 2
124 #define UNIFY_ALLOW_DERIVED 4
125 #define UNIFY_ALLOW_INTEGER 8
126 #define UNIFY_ALLOW_OUTER_LEVEL 16
127 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
128 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
131 tbr_incomplete_type,
132 tbr_ambiguous_baseclass,
133 tbr_success
134 };
157 tree);
214 location_t);
225 /* Make the current scope suitable for access checking when we are
226 processing T. T can be FUNCTION_DECL for instantiated function
227 template, VAR_DECL for static member variable, or TYPE_DECL for
228 alias template (needed by instantiate_decl). */
230 static void
232 {
240 else
244 {
245 saved_access_scope = tree_cons
248 }
249 }
251 /* Restore the scope set up by push_access_scope. T is the node we
252 are processing. */
254 static void
256 {
258 {
261 }
265 else
267 }
269 /* Do any processing required when DECL (a member template
270 declaration) is finished. Returns the TEMPLATE_DECL corresponding
271 to DECL, unless it is a specialization, in which case the DECL
272 itself is returned. */
274 tree
276 {
283 {
284 tree type;
292 {
296 }
298 }
302 {
304 {
307 }
308 else
310 }
311 else
315 }
317 /* Create a template info node. */
319 tree
321 {
326 }
328 /* Return the template info node corresponding to T, whatever T is. */
330 tree
332 {
354 }
356 /* Returns the template nesting level of the indicated class TYPE.
358 For example, in:
359 template <class T>
360 struct A
361 {
362 template <class U>
363 struct B {};
364 };
366 A<T>::B<U> has depth two, while A<T> has depth one.
367 Both A<T>::B<int> and A<int>::B<U> have depth one, if
368 they are instantiations, not specializations.
370 This function is guaranteed to return 0 if passed NULL_TREE so
371 that, for example, `template_class_depth (current_class_type)' is
372 always safe. */
374 int
376 {
380 {
391 else
393 }
396 }
398 /* Subroutine of maybe_begin_member_template_processing.
399 Returns true if processing DECL needs us to push template parms. */
401 static bool
403 {
409 }
411 /* Subroutine of maybe_begin_member_template_processing.
412 Push the template parms in PARMS, starting from LEVELS steps into the
413 chain, and ending at the beginning, since template parms are listed
414 innermost first. */
416 static void
418 {
426 current_template_parms
432 NULL);
434 {
443 {
450 /* Push the CONST_DECL. */
456 }
457 }
458 }
460 /* Restore the template parameter context for a member template, a
461 friend template defined in a class definition, or a non-template
462 member of template class. */
464 void
466 {
467 tree parms;
472 {
475 /* Disregard full specializations (c++/60999). */
478 }
481 {
486 {
489 }
492 }
494 /* Remember how many levels of template parameters we pushed so that
495 we can pop them later. */
497 }
499 /* Undo the effects of maybe_begin_member_template_processing. */
501 void
503 {
512 {
516 }
517 }
519 /* Return a new template argument vector which contains all of ARGS,
520 but has as its innermost set of arguments the EXTRA_ARGS. */
522 static tree
524 {
525 tree new_args;
543 }
545 /* Like add_to_template_args, but only the outermost ARGS are added to
546 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
547 (EXTRA_ARGS) levels are added. This function is used to combine
548 the template arguments from a partial instantiation with the
549 template arguments used to attain the full instantiation from the
550 partial instantiation. */
552 static tree
554 {
555 tree new_args;
557 /* If there are more levels of EXTRA_ARGS than there are ARGS,
558 something very fishy is going on. */
561 /* If *all* the new arguments will be the EXTRA_ARGS, just return
562 them. */
566 /* For the moment, we make ARGS look like it contains fewer levels. */
571 /* Now, we restore ARGS to its full dimensions. */
575 }
577 /* Return the N levels of innermost template arguments from the ARGS. */
579 tree
581 {
582 tree new_args;
588 /* If N is 1, just return the innermost set of template arguments. */
592 /* If we're not removing anything, just return the arguments we were
593 given. */
599 /* Make a new set of arguments, not containing the outer arguments. */
606 }
608 /* The inverse of get_innermost_template_args: Return all but the innermost
609 EXTRA_LEVELS levels of template arguments from the ARGS. */
611 static tree
613 {
614 tree new_args;
620 /* If N is 1, just return the outermost set of template arguments. */
624 /* If we're not removing anything, just return the arguments we were
625 given. */
630 /* Make a new set of arguments, not containing the inner arguments. */
637 }
639 /* We've got a template header coming up; push to a new level for storing
640 the parms. */
642 void
644 {
645 /* We use a non-tag-transparent scope here, which causes pushtag to
646 put tags in this scope, rather than in the enclosing class or
647 namespace scope. This is the right thing, since we want
648 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
649 global template class, push_template_decl handles putting the
650 TEMPLATE_DECL into top-level scope. For a nested template class,
651 e.g.:
653 template <class T> struct S1 {
654 template <class T> struct S2 {};
655 };
657 pushtag contains special code to insert the TEMPLATE_DECL for S2
658 at the right scope. */
664 /* Add a dummy parameter level while we process the parameter list. */
665 current_template_parms
668 current_template_parms);
669 }
671 /* This routine is called when a specialization is declared. If it is
672 invalid to declare a specialization here, an error is reported and
673 false is returned, otherwise this routine will return true. */
675 static bool
677 {
680 /* [temp.expl.spec]
682 An explicit specialization shall be declared in the namespace of
683 which the template is a member, or, for member templates, in the
684 namespace of which the enclosing class or enclosing class
685 template is a member. An explicit specialization of a member
686 function, member class or static data member of a class template
687 shall be declared in the namespace of which the class template
688 is a member. */
690 {
693 }
695 /* [temp.expl.spec]
697 In an explicit specialization declaration for a member of a class
698 template or a member template that appears in namespace scope,
699 the member template and some of its enclosing class templates may
700 remain unspecialized, except that the declaration shall not
701 explicitly specialize a class member template if its enclosing
702 class templates are not explicitly specialized as well. */
704 {
707 }
710 }
712 /* We've just seen template <>. */
714 bool
716 {
720 }
722 /* Called at then end of processing a declaration preceded by
723 template<>. */
725 void
727 {
730 }
732 /* Any template <>'s that we have seen thus far are not referring to a
733 function specialization. */
735 void
737 {
740 }
742 /* We've just seen a template header. If SPECIALIZATION is nonzero,
743 it was of the form template <>. */
745 static void
747 {
749 template_header_count++;
750 }
752 /* We're beginning an explicit instantiation. */
754 void
756 {
759 }
762 void
764 {
767 }
769 /* An explicit specialization or partial specialization of TMPL is being
770 declared. Check that the namespace in which the specialization is
771 occurring is permissible. Returns false iff it is invalid to
772 specialize TMPL in the current namespace. */
774 static bool
776 {
779 /* [tmpl.expl.spec]
781 An explicit specialization shall be declared in a namespace enclosing the
782 specialized template. An explicit specialization whose declarator-id is
783 not qualified shall be declared in the nearest enclosing namespace of the
784 template, or, if the namespace is inline (7.3.1), any namespace from its
785 enclosing namespace set. */
788 {
791 }
794 /* Same or enclosing namespace. */
796 else
797 {
803 }
804 }
806 /* SPEC is an explicit instantiation. Check that it is valid to
807 perform this explicit instantiation in the current namespace. */
809 static void
811 {
812 tree ns;
814 /* DR 275: An explicit instantiation shall appear in an enclosing
815 namespace of its template. */
821 }
823 // Returns the type of a template specialization only if that
824 // specialization needs to be defined. Otherwise (e.g., if the type has
825 // already been defined), the function returns NULL_TREE.
826 static tree
828 {
829 // An implicit instantiation of an incomplete type implies
830 // the definition of a new class template.
831 //
832 // template<typename T>
833 // struct S;
834 //
835 // template<typename T>
836 // struct S<T*>;
837 //
838 // Here, S<T*> is an implicit instantiation of S whose type
839 // is incomplete.
843 // It can also be the case that TYPE is a completed specialization.
844 // Continuing the previous example, suppose we also declare:
845 //
846 // template<typename T>
847 // requires Integral<T>
848 // struct S<T*>;
849 //
850 // Here, S<T*> refers to the specialization S<T*> defined
851 // above. However, we need to differentiate definitions because
852 // we intend to define a new partial specialization. In this case,
853 // we rely on the fact that the constraints are different for
854 // this declaration than that above.
855 //
856 // Note that we also get here for injected class names and
857 // late-parsed template definitions. We must ensure that we
858 // do not create new type declarations for those cases.
860 {
864 // If there are no template parameters, this cannot be a new
865 // partial template specializtion?
869 // The injected-class-name is not a new partial specialization.
873 // If the constraints are not the same as those of the primary
874 // then, we can probably create a new specialization.
878 {
882 }
884 // Also, if there's a pre-existing specialization with matching
885 // constraints, then this also isn't new.
888 {
896 }
898 // Create a new type node (and corresponding type decl)
899 // for the newly declared specialization.
904 /* We only need a separate type node for storing the definition of this
905 partial specialization; uses of S<T*> are unconstrained, so all are
906 equivalent. So keep TYPE_CANONICAL the same. */
909 // Build the corresponding type decl.
915 }
918 }
920 /* The TYPE is being declared. If it is a template type, that means it
921 is a partial specialization. Do appropriate error-checking. */
923 tree
925 {
926 tree context;
931 /* A lambda that appears in specialization context is not itself a
932 specialization. */
937 {
941 }
946 {
952 else
955 }
957 {
958 /* This is for ordinary explicit specialization and partial
959 specialization of a template class such as:
961 template <> class C<int>;
963 or:
965 template <class T> class C<T*>;
967 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
970 {
977 {
982 }
983 }
989 /* Trying to define a specialization either without a template<> header
990 or in an inappropriate place. We've already given an error, so just
991 bail now so we don't actually define the specialization. */
993 }
999 {
1000 /* This is for an explicit specialization of member class
1001 template according to [temp.expl.spec/18]:
1003 template <> template <class U> class C<int>::D;
1005 The context `C<int>' must be an implicit instantiation.
1006 Otherwise this is just a member class template declared
1007 earlier like:
1009 template <> class C<int> { template <class U> class D; };
1010 template <> template <class U> class C<int>::D;
1012 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1013 while in the second case, `C<int>::D' is a primary template
1014 and `C<T>::D' may not exist. */
1018 {
1019 tree t;
1024 {
1029 }
1031 /* Check for invalid specialization after instantiation:
1033 template <> template <> class C<int>::D<int>;
1034 template <> template <class U> class C<int>::D; */
1038 {
1042 {
1043 /* We already have a full specialization of this partial
1044 instantiation, or a full specialization has been
1045 looked up but not instantiated. Reassign it to the
1046 new member specialization template. */
1047 spec_entry elt;
1059 spec_entry **slot
1064 }
1065 else
1066 /* But if we've had an implicit instantiation, that's a
1067 problem ([temp.expl.spec]/6). */
1070 }
1072 /* Mark TYPE as a specialization. And as a result, we only
1073 have one level of template argument for the innermost
1074 class template. */
1079 }
1080 }
1082 {
1083 /* Someday C++0x may allow for enum template specialization. */
1088 else
1089 {
1092 }
1093 }
1096 }
1098 /* Returns nonzero if we can optimize the retrieval of specializations
1099 for TMPL, a TEMPLATE_DECL. In particular, for such a template, we
1100 do not use DECL_TEMPLATE_SPECIALIZATIONS at all. */
1104 {
1107 /* DECL_CLASS_SCOPE_P holds of T::f even if T is a template
1108 parameter. */
1110 /* The optimized lookup depends on the fact that the
1111 template arguments for the member function template apply
1112 purely to the containing class, which is not true if the
1113 containing class is an explicit or partial
1114 specialization. */
1118 /* It is possible to have a template that is not a member
1119 template and is not a member of a template class:
1121 template <typename T>
1122 struct S { friend A::f(); };
1124 Here, the friend function is a template, but the context does
1125 not have template information. The optimized lookup relies
1126 on having ARGS be the template arguments for both the class
1127 and the function template. */
1129 }
1131 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1132 gone through coerce_template_parms by now. */
1134 static void
1136 {
1139 {
1142 {
1149 /* Allow typedefs on the type of a non-type argument, since a
1151 else
1153 }
1154 }
1156 }
1158 /* Retrieve the specialization (in the sense of [temp.spec] - a
1159 specialization is either an instantiation or an explicit
1160 specialization) of TMPL for the given template ARGS. If there is
1161 no such specialization, return NULL_TREE. The ARGS are a vector of
1162 arguments, or a vector of vectors of arguments, in the case of
1163 templates with more than one level of parameters.
1165 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1166 then we search for a partial specialization matching ARGS. This
1167 parameter is ignored if TMPL is not a class template.
1169 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1170 result is a NONTYPE_ARGUMENT_PACK. */
1172 static tree
1174 {
1184 /* There should be as many levels of arguments as there are
1185 levels of parameters. */
1194 /* Lambda functions in templates aren't instantiated normally, but through
1195 tsubst_lambda_expr. */
1200 {
1201 /* The template arguments actually apply to the containing
1202 class. Find the class specialization with those
1203 arguments. */
1205 tree class_specialization
1210 /* Find the instance of TMPL. */
1213 {
1216 /* using-declarations can add base methods to the method vec,
1217 and we don't want those here. */
1220 }
1222 }
1223 else
1224 {
1226 spec_entry elt;
1235 else
1243 }
1246 }
1248 /* Like retrieve_specialization, but for local declarations. */
1250 tree
1252 {
1258 }
1260 /* Returns nonzero iff DECL is a specialization of TMPL. */
1262 int
1264 {
1265 tree t;
1268 {
1274 }
1275 else
1276 {
1285 }
1288 }
1290 /* Returns nonzero iff DECL is a specialization of friend declaration
1291 FRIEND_DECL according to [temp.friend]. */
1293 bool
1295 {
1302 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1303 of a template class, we want to check if DECL is a specialization
1304 if this. */
1308 {
1309 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1312 }
1317 /* There is nothing to do if this is not a template friend. */
1324 /* [temp.friend/6]
1325 A member of a class template may be declared to be a friend of a
1326 non-template class. In this case, the corresponding member of
1327 every specialization of the class template is a friend of the
1328 class granting friendship.
1330 For example, given a template friend declaration
1332 template <class T> friend void A<T>::f();
1334 the member function below is considered a friend
1336 template <> struct A<int> {
1337 void f();
1338 };
1340 For this type of template friend, TEMPLATE_DEPTH below will be
1341 nonzero. To determine if DECL is a friend of FRIEND, we first
1342 check if the enclosing class is a specialization of another. */
1349 {
1350 /* Next, we check the members themselves. In order to handle
1351 a few tricky cases, such as when FRIEND_DECL's are
1353 template <class T> friend void A<T>::g(T t);
1354 template <class T> template <T t> friend void A<T>::h();
1356 and DECL's are
1358 void A<int>::g(int);
1359 template <int> void A<int>::h();
1361 we need to figure out ARGS, the template arguments from
1362 the context of DECL. This is required for template substitution
1363 of `T' in the function parameter of `g' and template parameter
1364 of `h' in the above examples. Here ARGS corresponds to `int'. */
1371 {
1373 {
1376 else
1378 current_depth++;
1379 }
1381 }
1384 {
1386 tree friend_type;
1387 tree decl_type;
1388 tree friend_args_type;
1389 tree decl_args_type;
1391 /* Make sure that both DECL and FRIEND_DECL are templates or
1392 non-templates. */
1398 {
1399 /* If both are templates, check template parameter list. */
1400 tree friend_parms
1405 friend_parms))
1409 }
1410 else
1418 /* Check if return types match. */
1422 /* Check if function parameter types match, ignoring the
1423 `this' parameter. */
1432 }
1433 else
1434 {
1435 /* DECL is a TYPE_DECL */
1439 /* Make sure that both DECL and FRIEND_DECL are templates or
1440 non-templates. */
1441 is_template
1448 {
1449 tree friend_parms;
1450 /* If both are templates, check the name of the two
1451 TEMPLATE_DECL's first because is_friend didn't. */
1456 /* Now check template parameter list. */
1457 friend_parms
1460 return comp_template_parms
1462 friend_parms);
1463 }
1464 else
1467 }
1468 }
1470 }
1472 /* Register the specialization SPEC as a specialization of TMPL with
1473 the indicated ARGS. IS_FRIEND indicates whether the specialization
1474 is actually just a friend declaration. Returns SPEC, or an
1475 equivalent prior declaration, if available.
1477 We also store instantiations of field packs in the hash table, even
1478 though they are not themselves templates, to make lookup easier. */
1480 static tree
1482 hashval_t hash)
1483 {
1484 tree fn;
1486 spec_entry elt;
1494 /* This is the FUNCTION_DECL for a partial instantiation. Don't
1495 register it; we want the corresponding TEMPLATE_DECL instead.
1496 We use `uses_template_parms (DECL_TI_ARGS (spec))' rather than
1497 the more obvious `uses_template_parms (spec)' to avoid problems
1498 with default function arguments. In particular, given
1499 something like this:
1501 template <class T> void f(T t1, T t = T())
1503 the default argument expression is not substituted for in an
1504 instantiation unless and until it is actually needed. */
1508 /* We don't put these specializations in the hash table, but we might
1509 want to give an error about a mismatch. */
1511 else
1512 {
1520 slot =
1524 else
1526 }
1528 /* We can sometimes try to re-register a specialization that we've
1529 already got. In particular, regenerate_decl_from_template calls
1530 duplicate_decls which will update the specialization list. But,
1531 we'll still get called again here anyhow. It's more convenient
1532 to simply allow this than to try to prevent it. */
1536 {
1538 {
1541 {
1543 fn);
1545 }
1546 else
1547 {
1548 tree clone;
1549 /* This situation should occur only if the first
1550 specialization is an implicit instantiation, the
1551 second is an explicit specialization, and the
1552 implicit instantiation has not yet been used. That
1553 situation can occur if we have implicitly
1554 instantiated a member function and then specialized
1555 it later.
1557 We can also wind up here if a friend declaration that
1558 looked like an instantiation turns out to be a
1559 specialization:
1561 template <class T> void foo(T);
1562 class S { friend void foo<>(int) };
1563 template <> void foo(int);
1565 We transform the existing DECL in place so that any
1566 pointers to it become pointers to the updated
1567 declaration.
1569 If there was a definition for the template, but not
1570 for the specialization, we want this to look as if
1571 there were no definition, and vice versa. */
1574 /* The call to duplicate_decls will have applied
1575 [temp.expl.spec]:
1577 An explicit specialization of a function template
1578 is inline only if it is explicitly declared to be,
1579 and independently of whether its function template
1580 is.
1582 to the primary function; now copy the inline bits to
1583 the various clones. */
1585 {
1592 }
1596 }
1597 }
1599 {
1602 /* We've already complained in duplicate_decls. */
1606 /* Dup decl failed, but this is a new definition. Set the
1607 line number so any errors match this new
1608 definition. */
1612 }
1613 }
1617 /* A specialization must be declared in the same namespace as the
1618 template it is specializing. */
1624 {
1633 /* If TMPL is a forward declaration of a template function, keep a list
1634 of all specializations in case we need to reassign them to a friend
1635 template later in tsubst_friend_function.
1637 Also keep a list of all variable template instantiations so that
1638 process_partial_specialization can check whether a later partial
1639 specialization would have used it. */
1642 }
1645 }
1647 /* Returns true iff two spec_entry nodes are equivalent. */
1651 bool
1653 {
1660 /* tmpl could be a FIELD_DECL for a capture pack. */
1664 {
1665 /* Partial specializations of a variable template can be distinguished by
1666 constraints. */
1670 }
1674 }
1676 /* Returns a hash for a template TMPL and template arguments ARGS. */
1678 static hashval_t
1680 {
1683 }
1685 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1686 ignoring SPEC. */
1688 hashval_t
1690 {
1692 }
1694 /* Recursively calculate a hash value for a template argument ARG, for use
1695 in the hash tables of template specializations. */
1697 hashval_t
1699 {
1719 {
1727 {
1732 }
1754 {
1758 {
1761 }
1763 }
1767 {
1770 }
1781 val = iterative_hash_template_arg
1793 val);
1795 val);
1804 /* A lambda can't appear in a template arg, but don't crash on
1805 erroneous input. */
1817 /* Now hash operands as usual. */
1822 }
1825 {
1828 {
1829 // We want an alias specialization that survived strip_typedefs
1830 // to hash differently from its TYPE_CANONICAL, to avoid hash
1831 // collisions that compare as different in template_args_equal.
1832 // These could be dependent specializations that strip_typedefs
1833 // left alone, or untouched specializations because
1834 // coerce_template_parms returns the unconverted template
1835 // arguments if it sees incomplete argument packs.
1838 }
1841 val);
1844 /* Otherwise just compare the types during lookup. */
1853 {
1858 }
1859 }
1862 }
1864 /* Unregister the specialization SPEC as a specialization of TMPL.
1865 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1866 if the SPEC was listed as a specialization of TMPL.
1868 Note that SPEC has been ggc_freed, so we can't look inside it. */
1870 bool
1872 {
1874 spec_entry elt;
1882 {
1887 }
1890 }
1892 /* Like register_specialization, but for local declarations. We are
1893 registering SPEC, an instantiation of TMPL. */
1895 void
1897 {
1900 }
1902 /* TYPE is a class type. Returns true if TYPE is an explicitly
1903 specialized class. */
1905 bool
1907 {
1911 }
1913 /* Print the list of functions at FNS, going through all the overloads
1914 for each element of the list. Alternatively, FNS can not be a
1915 TREE_LIST, in which case it will be printed together with all the
1916 overloads.
1918 MORE and *STR should respectively be FALSE and NULL when the function
1919 is called from the outside. They are used internally on recursive
1920 calls. print_candidates manages the two parameters and leaves NULL
1921 in *STR when it ends. */
1923 static void
1925 {
1929 else
1931 {
1937 {
1940 else
1943 }
1945 }
1946 }
1948 /* Print the list of candidate FNS in an error message. FNS can also
1949 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
1951 void
1953 {
1957 }
1959 /* Get a (possibly) constrained template declaration for the
1960 purpose of ordering candidates. */
1961 static tree
1963 {
1969 }
1971 /* Among candidates having the same signature, return the
1972 most constrained or NULL_TREE if there is no best candidate.
1973 If the signatures of candidates vary (e.g., template
1974 specialization vs. member function), then there can be no
1975 most constrained.
1977 Note that we don't compare constraints on the functions
1978 themselves, but rather those of their templates. */
1979 static tree
1981 {
1982 // Try to find the best candidate in a first pass.
1985 {
1992 }
1994 // Verify that the champ is better than previous candidates.
1999 }
2002 }
2005 /* Returns the template (one of the functions given by TEMPLATE_ID)
2006 which can be specialized to match the indicated DECL with the
2007 explicit template args given in TEMPLATE_ID. The DECL may be
2008 NULL_TREE if none is available. In that case, the functions in
2009 TEMPLATE_ID are non-members.
2011 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2012 specialization of a member template.
2014 The TEMPLATE_COUNT is the number of references to qualifying
2015 template classes that appeared in the name of the function. See
2016 check_explicit_specialization for a more accurate description.
2018 TSK indicates what kind of template declaration (if any) is being
2019 declared. TSK_TEMPLATE indicates that the declaration given by
2020 DECL, though a FUNCTION_DECL, has template parameters, and is
2021 therefore a template function.
2023 The template args (those explicitly specified and those deduced)
2024 are output in a newly created vector *TARGS_OUT.
2026 If it is impossible to determine the result, an error message is
2027 issued. The error_mark_node is returned to indicate failure. */
2029 static tree
2031 tree decl,
2035 tmpl_spec_kind tsk)
2036 {
2037 tree fns;
2038 tree targs;
2039 tree explicit_targs;
2042 /* A TREE_LIST of templates of which DECL may be a specialization.
2043 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2044 corresponding TREE_PURPOSE is the set of template arguments that,
2045 when used to instantiate the template, would produce a function
2046 with the signature of DECL. */
2056 /* We shouldn't be specializing a member template of an
2057 unspecialized class template; we already gave an error in
2058 check_specialization_scope, now avoid crashing. */
2061 {
2064 }
2072 /* Check for baselinks. */
2077 {
2080 }
2082 {
2085 }
2087 /* Count the number of template headers specified for this
2088 specialization. */
2098 {
2101 tf_warning_or_error,
2105 }
2107 {
2111 {
2112 tree decl_arg_types;
2113 tree fn_arg_types;
2114 tree insttype;
2116 /* In case of explicit specialization, we need to check if
2117 the number of template headers appearing in the specialization
2118 is correct. This is usually done in check_explicit_specialization,
2119 but the check done there cannot be exhaustive when specializing
2120 member functions. Consider the following code:
2122 template <> void A<int>::f(int);
2123 template <> template <> void A<int>::f(int);
2125 Assuming that A<int> is not itself an explicit specialization
2126 already, the first line specializes "f" which is a non-template
2127 member function, whilst the second line specializes "f" which
2128 is a template member function. So both lines are syntactically
2129 correct, and check_explicit_specialization does not reject
2130 them.
2132 Here, we can do better, as we are matching the specialization
2133 against the declarations. We count the number of template
2134 headers, and we check if they match TEMPLATE_COUNT + 1
2135 (TEMPLATE_COUNT is the number of qualifying template classes,
2136 plus there must be another header for the member template
2137 itself).
2139 Notice that if header_count is zero, this is not a
2140 specialization but rather a template instantiation, so there
2141 is no check we can perform here. */
2145 /* Check that the number of template arguments at the
2146 innermost level for DECL is the same as for FN. */
2154 /* DECL might be a specialization of FN. */
2158 /* For a non-static member function, we need to make sure
2159 that the const qualification is the same. Since
2160 get_bindings does not try to merge the "this" parameter,
2161 we must do the comparison explicitly. */
2167 /* Skip the "this" parameter and, for constructors of
2168 classes with virtual bases, the VTT parameter. A
2169 full specialization of a constructor will have a VTT
2170 parameter, but a template never will. */
2171 decl_arg_types
2173 fn_arg_types
2176 /* Function templates cannot be specializations; there are
2177 no partial specializations of functions. Therefore, if
2178 the type of DECL does not match FN, there is no
2179 match.
2181 Note that it should never be the case that we have both
2182 candidates added here, and for regular member functions
2183 below. */
2185 {
2189 }
2191 /* See whether this function might be a specialization of this
2192 template. Suppress access control because we might be trying
2193 to make this specialization a friend, and we have already done
2194 access control for the declaration of the specialization. */
2200 /* We cannot deduce template arguments that when used to
2201 specialize TMPL will produce DECL. */
2204 /* Remove, from the set of candidates, all those functions
2205 whose constraints are not satisfied. */
2209 // Then, try to form the new function type.
2213 fn_arg_types
2218 /* Save this template, and the arguments deduced. */
2220 }
2222 /* FN is an ordinary member function, and we need a
2223 specialization of a member template. */
2224 ;
2226 /* We can get IDENTIFIER_NODEs here in certain erroneous
2227 cases. */
2228 ;
2230 /* This is just an ordinary non-member function. Nothing can
2231 be a specialization of that. */
2232 ;
2234 /* Cannot specialize functions that are created implicitly. */
2235 ;
2236 else
2237 {
2238 tree decl_arg_types;
2240 /* This is an ordinary member function. However, since
2241 we're here, we can assume its enclosing class is a
2242 template class. For example,
2244 template <typename T> struct S { void f(); };
2245 template <> void S<int>::f() {}
2247 Here, S<int>::f is a non-template, but S<int> is a
2248 template class. If FN has the same type as DECL, we
2249 might be in business. */
2252 /* Its enclosing class is an explicit specialization
2253 of a template class. This is not a candidate. */
2258 /* The return types differ. */
2261 /* Adjust the type of DECL in case FN is a static member. */
2268 decl_arg_types))
2271 // If the deduced arguments do not satisfy the constraints,
2272 // this is not a candidate.
2276 // Add the candidate.
2278 }
2279 }
2282 {
2283 /* We have:
2285 [temp.expl.spec]
2287 It is possible for a specialization with a given function
2288 signature to be instantiated from more than one function
2289 template. In such cases, explicit specification of the
2290 template arguments must be used to uniquely identify the
2291 function template specialization being specialized.
2293 Note that here, there's no suggestion that we're supposed to
2294 determine which of the candidate templates is most
2295 specialized. However, we, also have:
2297 [temp.func.order]
2299 Partial ordering of overloaded function template
2300 declarations is used in the following contexts to select
2301 the function template to which a function template
2302 specialization refers:
2304 -- when an explicit specialization refers to a function
2305 template.
2307 So, we do use the partial ordering rules, at least for now.
2308 This extension can only serve to make invalid programs valid,
2309 so it's safe. And, there is strong anecdotal evidence that
2310 the committee intended the partial ordering rules to apply;
2311 the EDG front end has that behavior, and John Spicer claims
2312 that the committee simply forgot to delete the wording in
2313 [temp.expl.spec]. */
2316 {
2319 }
2320 }
2322 // Concepts allows multiple declarations of member functions
2323 // with the same signature. Like above, we need to rely on
2324 // on the partial ordering of those candidates to determine which
2325 // is the best.
2327 {
2329 {
2332 }
2333 }
2336 {
2343 else
2346 }
2350 {
2356 }
2358 /* We have one, and exactly one, match. */
2360 {
2364 // Propagate the candidate's constraints to the declaration.
2367 /* DECL is a re-declaration or partial instantiation of a template
2368 function. */
2371 /* It was a specialization of an ordinary member function in a
2372 template class. */
2374 }
2376 /* It was a specialization of a template. */
2379 {
2384 }
2385 else
2388 }
2390 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2391 but with the default argument values filled in from those in the
2392 TMPL_TYPES. */
2394 static tree
2396 tree tmpl_types)
2397 {
2398 tree new_spec_types;
2406 /* Substitute into the rest of the list. */
2407 new_spec_types =
2411 /* Add the default argument for this parameter. */
2414 new_spec_types);
2415 }
2417 /* DECL is an explicit specialization. Replicate default arguments
2418 from the template it specializes. (That way, code like:
2420 template <class T> void f(T = 3);
2421 template <> void f(double);
2422 void g () { f (); }
2424 works, as required.) An alternative approach would be to look up
2425 the correct default arguments at the call-site, but this approach
2426 is consistent with how implicit instantiations are handled. */
2428 static void
2430 {
2431 tree tmpl;
2432 tree spec_types;
2433 tree tmpl_types;
2434 tree new_spec_types;
2435 tree old_type;
2436 tree new_type;
2437 tree t;
2442 /* See if there's anything we need to do. */
2455 {
2456 /* Remove the this pointer, but remember the object's type for
2457 CV quals. */
2463 {
2464 /* DECL may contain more parameters than TMPL due to the extra
2465 in-charge parameter in constructors and destructors. */
2468 }
2470 {
2473 }
2474 }
2476 /* Compute the merged default arguments. */
2477 new_spec_types =
2480 /* Compute the new FUNCTION_TYPE. */
2482 {
2486 new_spec_types);
2489 /* Put the in-charge parameter back. */
2492 new_spec_types);
2496 new_spec_types);
2497 }
2498 else
2500 new_spec_types);
2510 }
2512 /* Return the number of template headers we expect to see for a definition
2513 or specialization of CTYPE or one of its non-template members. */
2515 int
2517 {
2521 {
2522 /* You're supposed to have one `template <...>' for every
2523 template class, but you don't need one for a full
2524 specialization. For example:
2526 template <class T> struct S{};
2527 template <> struct S<int> { void f(); };
2528 void S<int>::f () {}
2530 is correct; there shouldn't be a `template <>' for the
2531 definition of `S<int>::f'. */
2533 /* If CTYPE does not have template information of any
2534 kind, then it is not a template, nor is it nested
2535 within a template. */
2543 }
2546 }
2548 /* Do a simple sanity check on the template headers that precede the
2549 variable declaration DECL. */
2551 void
2553 {
2558 {
2561 "variable templates only available with "
2564 // Namespace-scope variable templates should have a template header.
2566 }
2568 {
2570 "too many template headers for %qD "
2576 "members of an explicitly specialized class are defined "
2578 }
2579 }
2581 /* An explicit specialization whose declarator-id or class-head-name is not
2582 qualified shall be declared in the nearest enclosing namespace of the
2583 template, or, if the namespace is inline (7.3.1), any namespace from its
2584 enclosing namespace set.
2586 If the name declared in the explicit instantiation is an unqualified name,
2587 the explicit instantiation shall appear in the namespace where its template
2588 is declared or, if that namespace is inline (7.3.1), any namespace from its
2589 enclosing namespace set. */
2591 void
2593 {
2598 {
2604 /* This was allowed in C++98, so only pedwarn. */
2606 "outside its namespace must use a nested-name-"
2608 }
2609 }
2611 /* Check to see if the function just declared, as indicated in
2612 DECLARATOR, and in DECL, is a specialization of a function
2613 template. We may also discover that the declaration is an explicit
2614 instantiation at this point.
2616 Returns DECL, or an equivalent declaration that should be used
2617 instead if all goes well. Issues an error message if something is
2618 amiss. Returns error_mark_node if the error is not easily
2619 recoverable.
2621 FLAGS is a bitmask consisting of the following flags:
2623 2: The function has a definition.
2624 4: The function is a friend.
2626 The TEMPLATE_COUNT is the number of references to qualifying
2627 template classes that appeared in the name of the function. For
2628 example, in
2630 template <class T> struct S { void f(); };
2631 void S<int>::f();
2633 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2634 classes are not counted in the TEMPLATE_COUNT, so that in
2636 template <class T> struct S {};
2637 template <> struct S<int> { void f(); }
2638 template <> void S<int>::f();
2640 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2641 invalid; there should be no template <>.)
2643 If the function is a specialization, it is marked as such via
2644 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2645 is set up correctly, and it is added to the list of specializations
2646 for that template. */
2648 tree
2650 tree decl,
2653 {
2662 tmpl_spec_kind tsk;
2665 {
2668 else
2670 }
2671 else
2675 {
2678 {
2681 }
2683 {
2685 /* This could be something like:
2687 template <class T> void f(T);
2688 class S { friend void f<>(int); } */
2690 else
2691 {
2692 /* This case handles bogus declarations like template <>
2693 template <class T> void f<int>(); */
2696 declarator);
2698 }
2699 }
2703 /* The error has already been reported in
2704 check_specialization_scope. */
2710 /* Fall through. */
2723 decl);
2726 else
2730 /* Fall through. */
2736 /* In cases like template<> constexpr bool v = true;
2737 We'll give an error in check_template_variable. */
2743 else
2749 {
2750 /* This case handles bogus declarations like template <>
2751 template <class T> void f<int>(); */
2755 declarator);
2757 {
2758 /* Partial specialization of variable template. */
2762 }
2766 else
2770 ok:;
2771 }
2774 /* This is a specialization of a member template, without
2775 specialization the containing class. Something like:
2777 template <class T> struct S {
2778 template <class U> void f (U);
2779 };
2780 template <> template <class U> void S<int>::f(U) {}
2782 That's a specialization -- but of the entire template. */
2788 }
2791 /* This doesn't apply to variable templates. */
2794 {
2798 {
2802 }
2803 }
2806 {
2811 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
2813 {
2814 tree fns;
2819 else
2820 {
2821 /* If there is no class context, the explicit instantiation
2822 must be at namespace scope. */
2825 /* Find the namespace binding, using the declaration
2826 context. */
2830 /* If lookup fails, look for a friend declaration so we can
2831 give a better diagnostic. */
2837 {
2840 }
2841 }
2844 }
2850 {
2852 /* A specialization in class scope. This is invalid,
2853 but the error will already have been flagged by
2854 check_specialization_scope. */
2856 else
2857 {
2858 /* It's not valid to write an explicit instantiation in
2859 class scope, e.g.:
2861 class C { template void f(); }
2863 This case is caught by the parser. However, on
2864 something like:
2866 template class C { void f(); };
2868 (which is invalid) we can get here. The error will be
2869 issued later. */
2870 ;
2871 }
2874 }
2877 {
2878 // We'll match variable templates in start_decl.
2882 /* Find the list of functions in ctype that have the same
2883 name as the declared function. */
2887 {
2891 {
2892 /* From [temp.expl.spec]:
2894 If such an explicit specialization for the member
2895 of a class template names an implicitly-declared
2896 special member function (clause _special_), the
2897 program is ill-formed.
2899 Similar language is found in [temp.explicit]. */
2902 }
2905 }
2907 /* For a type-conversion operator, We might be looking for
2908 `operator int' which will be a specialization of
2909 `operator T'. Grab all the conversion operators, and
2910 then select from them. */
2915 {
2918 }
2919 else
2921 }
2923 /* Figure out what exactly is being specialized at this point.
2924 Note that for an explicit instantiation, even one for a
2925 member function, we cannot tell a priori whether the
2926 instantiation is for a member template, or just a member
2927 function of a template class. Even if a member template is
2928 being instantiated, the member template arguments may be
2929 elided if they can be deduced from the rest of the
2930 declaration. */
2933 member_specialization,
2934 template_count,
2935 tsk);
2938 /* We couldn't figure out what this declaration was
2939 specializing. */
2941 else
2942 {
2945 {
2947 "friend declaration %qD is not visible to "
2951 }
2959 {
2960 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
2961 is done by do_decl_instantiation later. */
2967 {
2968 /* If TMPL is not the most general template (for
2969 example, if TMPL is a friend template that is
2970 injected into namespace scope), then there will
2971 be too many levels of TARGS. Remove some of them
2972 here. */
2974 tree new_targs;
2981 }
2984 }
2986 /* If we thought that the DECL was a member function, but it
2987 turns out to be specializing a static member function,
2988 make DECL a static member function as well. */
2994 /* If this is a specialization of a member template of a
2995 template class, we want to return the TEMPLATE_DECL, not
2996 the specialization of it. */
2998 {
3003 {
3004 tree parm;
3008 /* We want to use the argument list specified in the
3009 definition, not in the original declaration. */
3014 }
3017 }
3019 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3025 /* Inherit default function arguments from the template
3026 DECL is specializing. */
3030 /* This specialization has the same protection as the
3031 template it specializes. */
3035 /* 7.1.1-1 [dcl.stc]
3037 A storage-class-specifier shall not be specified in an
3038 explicit specialization...
3040 The parser rejects these, so unless action is taken here,
3041 explicit function specializations will always appear with
3042 global linkage.
3044 The action recommended by the C++ CWG in response to C++
3045 defect report 605 is to make the storage class and linkage
3046 of the explicit specialization match the templated function:
3048 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3049 */
3051 {
3055 /* A concept cannot be specialized. */
3057 {
3059 gen_tmpl);
3061 }
3063 /* This specialization has the same linkage and visibility as
3064 the function template it specializes. */
3067 {
3070 }
3073 {
3076 }
3077 }
3079 /* If DECL is a friend declaration, declared using an
3080 unqualified name, the namespace associated with DECL may
3081 have been set incorrectly. For example, in:
3083 template <typename T> void f(T);
3084 namespace N {
3085 struct S { friend void f<int>(int); }
3086 }
3088 we will have set the DECL_CONTEXT for the friend
3089 declaration to N, rather than to the global namespace. */
3094 /* This is not really a declaration of a specialization.
3095 It's just the name of an instantiation. But, it's not
3096 a request for an instantiation, either. */
3099 /* A specialization is not necessarily COMDAT. */
3105 /* If this is a full specialization, register it so that we can find
3106 it again. Partial specializations will be registered in
3107 process_partial_specialization. */
3112 /* A 'structor should already have clones. */
3118 }
3119 }
3122 }
3124 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3125 parameters. These are represented in the same format used for
3126 DECL_TEMPLATE_PARMS. */
3128 int
3130 {
3131 const_tree p1;
3132 const_tree p2;
3140 {
3152 {
3156 /* If either of the template parameters are invalid, assume
3157 they match for the sake of error recovery. */
3170 }
3171 }
3174 /* One set of parameters has more parameters lists than the
3175 other. */
3179 }
3181 /* Determine whether PARM is a parameter pack. */
3183 bool
3185 {
3186 /* Determine if we have a non-type template parameter pack. */
3193 /* If this is a list of template parameters, we could get a
3194 TYPE_DECL or a TEMPLATE_DECL. */
3198 /* Otherwise it must be a type template parameter. */
3202 }
3204 /* Determine if T is a function parameter pack. */
3206 bool
3208 {
3212 }
3214 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3215 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3217 tree
3219 {
3226 }
3228 /* Return true iff the function parameter PARAM_DECL was expanded
3229 from the function parameter pack PACK. */
3231 bool
3233 {
3238 /* The parameter pack and its pack arguments have the same
3239 DECL_PARM_INDEX. */
3241 }
3243 /* Determine whether ARGS describes a variadic template args list,
3244 i.e., one that is terminated by a template argument pack. */
3246 static bool
3248 {
3250 tree last_parm;
3264 }
3266 /* Generate a new name for the parameter pack name NAME (an
3267 IDENTIFIER_NODE) that incorporates its */
3269 static tree
3271 {
3272 /* Munge the name to include the parameter index. */
3273 #define NUMBUF_LEN 128
3287 }
3289 /* Return true if T is a primary function, class or alias template
3290 specialization, not including the template pattern. */
3292 bool
3294 {
3310 }
3312 /* Return true if PARM is a template template parameter. */
3314 bool
3316 {
3318 }
3320 /* Return true iff PARM is a DECL representing a type template
3321 parameter. */
3323 bool
3325 {
3330 }
3332 /* Return the template parameters of T if T is a
3333 primary template instantiation, NULL otherwise. */
3335 tree
3337 {
3342 parms = INNERMOST_TEMPLATE_PARMS
3346 }
3348 /* Return the template parameters of the LEVELth level from the full list
3349 of template parameters PARMS. */
3351 tree
3353 {
3354 tree p;
3365 }
3367 /* Returns the template arguments of T if T is a template instantiation,
3368 NULL otherwise. */
3370 tree
3372 {
3380 }
3382 /* Return the argument pack elements of T if T is a template argument pack,
3383 NULL otherwise. */
3385 tree
3387 {
3393 }
3395 /* True iff FN is a function representing a built-in variadic parameter
3396 pack. */
3398 bool
3400 {
3410 }
3412 /* True iff CALL is a call to a function representing a built-in variadic
3413 parameter pack. */
3415 static bool
3417 {
3421 }
3423 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3425 static tree
3427 tree in_decl)
3428 {
3434 {
3436 {
3439 }
3444 }
3445 else
3446 {
3450 /* Calculate the largest value of len that won't make the size of the vec
3451 overflow an int. The compiler will exceed resource limits long before
3452 this, but it seems a decent place to diagnose. */
3456 {
3461 }
3469 }
3470 }
3472 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3473 CALL. */
3475 static tree
3477 tree in_decl)
3478 {
3488 }
3490 /* Structure used to track the progress of find_parameter_packs_r. */
3491 struct find_parameter_pack_data
3492 {
3493 /* TREE_LIST that will contain all of the parameter packs found by
3494 the traversal. */
3497 /* Set of AST nodes that have been visited by the traversal. */
3500 /* True iff we're making a type pack expansion. */
3502 };
3504 /* Identifies all of the argument packs that occur in a template
3505 argument and appends them to the TREE_LIST inside DATA, which is a
3506 find_parameter_pack_data structure. This is a subroutine of
3507 make_pack_expansion and uses_parameter_packs. */
3508 static tree
3510 {
3516 /* Handle type aliases/typedefs. */
3518 {
3525 }
3527 /* Identify whether this is a parameter pack or not. */
3529 {
3537 /* FALLTHRU */
3539 /* If the placeholder appears in the decl-specifier-seq of a function
3540 parameter pack (14.6.3), or the type-specifier-seq of a type-id that
3541 is a pack expansion, the invented template parameter is a template
3542 parameter pack. */
3552 {
3553 /* We don't want to walk into the type of a PARM_DECL,
3554 because we don't want to see the type parameter pack. */
3557 }
3560 /* Look through a lambda capture proxy to the field pack. */
3563 {
3569 }
3571 {
3573 find_parameter_packs_r,
3576 }
3588 /* Not a parameter pack. */
3590 }
3593 {
3594 /* Add this parameter pack to the list. */
3596 }
3602 /* This switch statement will return immediately if we don't find a
3603 parameter pack. */
3605 {
3610 /* Check the template itself. */
3613 /* Check the template arguments. */
3627 /* Ignore the declaration of a capture proxy for a parameter pack. */
3635 /* Fall through. */
3680 {
3686 }
3689 {
3690 /* When traversing a DECLTYPE_TYPE_EXPR, we need to set
3691 type_pack_expansion_p to false so that any placeholders
3692 within the expression don't get marked as parameter packs. */
3700 }
3704 }
3707 }
3709 /* Determines if the expression or type T uses any parameter packs. */
3710 bool
3712 {
3721 }
3723 /* Turn ARG, which may be an expression, type, or a TREE_LIST
3724 representation a base-class initializer into a parameter pack
3725 expansion. If all goes well, the resulting node will be an
3726 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
3727 respectively. */
3728 tree
3730 {
3731 tree result;
3740 {
3741 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
3742 class initializer. In this case, the TREE_PURPOSE will be a
3743 _TYPE node (representing the base class expansion we're
3744 initializing) and the TREE_VALUE will be a TREE_LIST
3745 containing the initialization arguments.
3747 The resulting expansion looks somewhat different from most
3748 expansions. Rather than returning just one _EXPANSION, we
3749 return a TREE_LIST whose TREE_PURPOSE is a
3750 TYPE_PACK_EXPANSION containing the bases that will be
3751 initialized. The TREE_VALUE will be identical to the
3752 original TREE_VALUE, which is a list of arguments that will
3753 be passed to each base. We do not introduce any new pack
3754 expansion nodes into the TREE_VALUE (although it is possible
3755 that some already exist), because the TREE_PURPOSE and
3756 TREE_VALUE all need to be expanded together with the same
3757 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
3758 resulting TREE_PURPOSE will mention the parameter packs in
3759 both the bases and the arguments to the bases. */
3760 tree purpose;
3761 tree value;
3764 /* Determine which parameter packs will be used by the base
3765 class expansion. */
3774 {
3777 arg);
3780 }
3783 {
3784 /* Collect the sets of parameter packs used in each of the
3785 initialization arguments. */
3787 {
3788 /* Determine which parameter packs will be expanded in this
3789 argument. */
3792 }
3793 }
3797 /* Create the pack expansion type for the base type. */
3803 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3804 they will rarely be compared to anything. */
3808 }
3813 /* Build the PACK_EXPANSION_* node. */
3814 result = for_types
3819 {
3820 /* Propagate type and const-expression information. */
3823 /* Mark this read now, since the expansion might be length 0. */
3825 }
3826 else
3827 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
3828 they will rarely be compared to anything. */
3831 /* Determine which parameter packs will be expanded. */
3838 /* Make sure we found some parameter packs. */
3840 {
3842 {
3845 else
3847 }
3849 }
3855 }
3857 /* Checks T for any "bare" parameter packs, which have not yet been
3858 expanded, and issues an error if any are found. This operation can
3859 only be done on full expressions or types (e.g., an expression
3860 statement, "if" condition, etc.), because we could have expressions like:
3862 foo(f(g(h(args)))...)
3864 where "args" is a parameter pack. check_for_bare_parameter_packs
3865 should not be called for the subexpressions args, h(args),
3866 g(h(args)), or f(g(h(args))), because we would produce erroneous
3867 error messages.
3869 Returns TRUE and emits an error if there were bare parameter packs,
3870 returns FALSE otherwise. */
3871 bool
3873 {
3880 /* A lambda might use a parameter pack from the containing context. */
3894 {
3898 {
3909 else
3914 else
3918 }
3921 }
3924 }
3926 /* Expand any parameter packs that occur in the template arguments in
3927 ARGS. */
3928 tree
3930 {
3939 /* First, determine if we need to expand anything, and the number of
3940 slots we'll need. */
3942 {
3947 {
3951 else
3953 }
3954 else
3955 {
3957 num_result_args++;
3958 }
3959 }
3961 /* If no expansion is necessary, we're done. */
3965 /* Expand arguments. */
3968 non_default_args_count =
3971 {
3974 {
3981 }
3982 else
3983 {
3986 }
3987 }
3991 }
3993 /* Checks if DECL shadows a template parameter.
3995 [temp.local]: A template-parameter shall not be redeclared within its
3996 scope (including nested scopes).
3998 Emits an error and returns TRUE if the DECL shadows a parameter,
3999 returns FALSE otherwise. */
4001 bool
4003 {
4004 tree olddecl;
4006 /* If we're not in a template, we can't possibly shadow a template
4007 parameter. */
4011 /* Figure out what we're shadowing. */
4015 /* If there's no previous binding for this name, we're not shadowing
4016 anything, let alone a template parameter. */
4020 /* If we're not shadowing a template parameter, we're done. Note
4021 that OLDDECL might be an OVERLOAD (or perhaps even an
4022 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4023 node. */
4027 /* We check for decl != olddecl to avoid bogus errors for using a
4028 name inside a class. We check TPFI to avoid duplicate errors for
4029 inline member templates. */
4035 /* Don't complain about the injected class name, as we've already
4036 complained about the class itself. */
4043 else
4048 }
4050 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4051 ORIG_LEVEL, DECL, and TYPE. */
4053 static tree
4057 tree decl,
4058 tree type)
4059 {
4070 }
4072 /* Find the canonical type parameter for the given template type
4073 parameter. Returns the canonical type parameter, which may be TYPE
4074 if no such parameter existed. */
4076 static tree
4078 {
4079 tree list;
4093 else
4094 {
4098 }
4099 }
4101 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4102 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4103 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4104 new one is created. */
4106 static tree
4108 tsubst_flags_t complain)
4109 {
4114 {
4133 /* Template template parameters need this. */
4135 {
4142 }
4143 }
4146 }
4148 /* Process information from new template parameter PARM and append it
4149 to the LIST being built. This new parameter is a non-type
4150 parameter iff IS_NON_TYPE is true. This new parameter is a
4151 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4152 is in PARM_LOC. */
4154 tree
4157 {
4166 {
4170 {
4174 else
4176 }
4179 }
4182 {
4188 {
4189 /* [temp.param]
4191 The top-level cv-qualifiers on the template-parameter are
4192 ignored when determining its type. */
4197 && !is_parameter_pack
4198 /* If we're in a nested template parameter list, the template
4199 template parameter could be a parameter pack. */
4201 {
4202 /* This template parameter is not a parameter pack, but it
4203 should be. Complain about "bare" parameter packs. */
4206 /* Recover by calling this a parameter pack. */
4208 }
4209 }
4211 /* A template parameter is not modifiable. */
4220 processing_template_decl,
4225 }
4226 else
4227 {
4228 tree t;
4232 {
4234 /* This is for distinguishing between real templates and template
4235 template parameters */
4239 }
4240 else
4241 {
4243 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4246 }
4253 processing_template_decl,
4257 }
4261 /* Build requirements for the type/template parameter.
4262 This must be done after SET_DECL_TEMPLATE_PARM_P or
4263 process_template_parm could fail. */
4268 /* Build the parameter node linking the parameter declaration,
4269 its default argument (if any), and its constraints (if any). */
4274 }
4276 /* The end of a template parameter list has been reached. Process the
4277 tree list into a parameter vector, converting each parameter into a more
4278 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4279 as PARM_DECLs. */
4281 tree
4283 {
4288 /* Pop the dummy parameter level and add the real one. */
4291 current_template_parms
4296 {
4300 }
4305 }
4307 // Explicitly indicate the end of the template parameter list. We assume
4308 // that the current template parameters have been constructed and/or
4309 // managed explicitly, as when creating new template template parameters
4310 // from a shorthand constraint.
4311 void
4313 {
4315 }
4317 /* end_template_decl is called after a template declaration is seen. */
4319 void
4321 {
4327 /* This matches the pushlevel in begin_template_parm_list. */
4332 }
4334 /* Takes a TREE_LIST representing a template parameter and convert it
4335 into an argument suitable to be passed to the type substitution
4336 functions. Note that If the TREE_LIST contains an error_mark
4337 node, the returned argument is error_mark_node. */
4339 tree
4341 {
4354 {
4358 {
4359 /* Turn this argument into a TYPE_ARGUMENT_PACK
4360 with a single element, which expands T. */
4369 }
4370 }
4371 else
4372 {
4376 {
4377 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4378 with a single element, which expands T. */
4388 }
4389 else
4391 }
4393 }
4395 /* Given a single level of template parameters (a TREE_VEC), return it
4396 as a set of template arguments. */
4398 static tree
4400 {
4410 }
4412 /* Given a set of template parameters, return them as a set of template
4413 arguments. The template parameters are represented as a TREE_VEC, in
4414 the form documented in cp-tree.h for template arguments. */
4416 static tree
4418 {
4419 tree header;
4424 /* If there is only one level of template parameters, we do not
4425 create a TREE_VEC of TREE_VECs. Instead, we return a single
4426 TREE_VEC containing the arguments. */
4431 {
4436 else
4438 }
4441 }
4443 /* Within the declaration of a template, return the currently active
4444 template parameters as an argument TREE_VEC. */
4446 static tree
4448 {
4450 }
4452 /* Update the declared TYPE by doing any lookups which were thought to be
4453 dependent, but are not now that we know the SCOPE of the declarator. */
4455 tree
4457 {
4468 /* Don't bother building up the args in this case. */
4470 {
4471 /* tsubst in the args corresponding to the template parameters,
4472 including auto if present. Most things will be unchanged, but
4473 make_typename_type and tsubst_qualified_id will resolve
4474 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
4477 tree pushed;
4479 {
4483 }
4488 }
4494 {
4497 else
4499 }
4501 }
4503 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
4504 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
4505 the new template is a member template. */
4507 tree
4509 {
4517 }
4519 struct template_parm_data
4520 {
4521 /* The level of the template parameters we are currently
4522 processing. */
4525 /* The index of the specialization argument we are currently
4526 processing. */
4529 /* An array whose size is the number of template parameters. The
4530 elements are nonzero if the parameter has been used in any one
4531 of the arguments processed so far. */
4534 /* An array whose size is the number of template arguments. The
4535 elements are nonzero if the argument makes use of template
4536 parameters of this level. */
4538 };
4540 /* Subroutine of push_template_decl used to see if each template
4541 parameter in a partial specialization is used in the explicit
4542 argument list. If T is of the LEVEL given in DATA (which is
4543 treated as a template_parm_data*), then DATA->PARMS is marked
4544 appropriately. */
4546 static int
4548 {
4556 {
4559 }
4561 /* In C++17 the type of a non-type argument is a deduced context. */
4566 data,
4567 NULL,
4570 /* Return zero so that for_each_template_parm will continue the
4571 traversal of the tree; we want to mark *every* template parm. */
4573 }
4575 /* Process the partial specialization DECL. */
4577 static tree
4579 {
4586 tree inner_parms;
4587 tree inst;
4597 /* A concept cannot be specialized. */
4599 {
4602 }
4607 /* We check that each of the template parameters given in the
4608 partial specialization is used in the argument list to the
4609 specialization. For example:
4611 template <class T> struct S;
4612 template <class T> struct S<T*>;
4614 The second declaration is OK because `T*' uses the template
4615 parameter T, whereas
4617 template <class T> struct S<int>;
4619 is no good. Even trickier is:
4621 template <class T>
4622 struct S1
4623 {
4624 template <class U>
4625 struct S2;
4626 template <class U>
4627 struct S2<T>;
4628 };
4630 The S2<T> declaration is actually invalid; it is a
4631 full-specialization. Of course,
4633 template <class U>
4634 struct S2<T (*)(U)>;
4636 or some such would have been OK. */
4644 {
4649 NULL,
4651 }
4654 {
4655 /* One of the template parms was not used in a deduced context in the
4656 specialization. */
4658 {
4662 }
4666 }
4671 /* [temp.class.spec]
4673 The argument list of the specialization shall not be identical to
4674 the implicit argument list of the primary template. */
4675 tree main_args
4678 && (!flag_concepts
4681 {
4685 else
4689 }
4691 /* A partial specialization that replaces multiple parameters of the
4692 primary template with a pack expansion is less specialized for those
4693 parameters. */
4695 {
4697 "primary template because it replaces multiple parameters "
4700 /* Avoid crash in process_partial_specialization. */
4702 }
4704 /* If we aren't in a dependent class, we can actually try deduction. */
4706 /* FIXME we should be able to handle a partial specialization of a
4707 partial instantiation, but currently we can't (c++/41727). */
4710 {
4714 maintmpl);
4715 }
4717 /* [temp.class.spec]
4719 A partially specialized non-type argument expression shall not
4720 involve template parameters of the partial specialization except
4721 when the argument expression is a simple identifier.
4723 The type of a template parameter corresponding to a specialized
4724 non-type argument shall not be dependent on a parameter of the
4725 specialization.
4727 Also, we verify that pack expansions only occur at the
4728 end of the argument list. */
4732 {
4739 {
4740 /* Extract the arguments from the argument pack. We'll be
4741 iterating over these in the following loop. */
4744 }
4747 {
4749 /* Get the Jth argument in the parameter pack. */
4753 {
4754 /* Pack expansions must come at the end of the
4755 argument list. */
4758 {
4762 else
4765 }
4766 }
4769 /* We only care about the pattern. */
4775 /* This next two lines are the `argument expression is not just a
4776 simple identifier' condition and also the `specialized
4777 non-type argument' bit. */
4781 {
4785 arg);
4786 else
4787 {
4788 /* Look at the corresponding template parameter,
4789 marking which template parameters its type depends
4790 upon. */
4794 {
4795 /* We haven't yet initialized TPD2. Do so now. */
4797 /* The number of parameters here is the number in the
4798 main template, which, as checked in the assertion
4799 above, is NARGS. */
4803 }
4805 /* Mark the template parameters. But this time, we're
4806 looking for the template parameters of the main
4807 template, not in the specialization. */
4814 NULL,
4818 {
4819 /* The type depended on some template parameters.
4820 If they are fully specialized in the
4821 specialization, that's OK. */
4830 "type %qT of template argument %qE depends "
4832 "type %qT of template argument %qE depends "
4834 type,
4835 arg);
4836 }
4837 }
4838 }
4839 }
4840 }
4842 /* We should only get here once. */
4846 // Build the template decl.
4855 /* Give template template parms a DECL_CONTEXT of the template
4856 for which they are a parameter. */
4858 {
4862 }
4865 /* We didn't register this in check_explicit_specialization so we could
4866 wait until the constraints were set. */
4868 else
4878 {
4884 {
4892 "declaration of %qD ambiguates earlier template "
4896 "partial specialization of %qD after instantiation "
4898 }
4899 }
4902 }
4904 /* PARM is a template parameter of some form; return the corresponding
4905 TEMPLATE_PARM_INDEX. */
4907 static tree
4909 {
4922 }
4924 /* Subroutine of fixed_parameter_pack_p below. Look for any template
4925 parameter packs used by the template parameter PARM. */
4927 static void
4929 {
4930 /* A type parm can't refer to another parm. */
4934 {
4938 }
4945 }
4947 /* PARM is a template parameter pack. Return any parameter packs used in
4948 its type or the type of any of its template parameters. If there are
4949 any such packs, it will be instantiated into a fixed template parameter
4950 list by partial instantiation rather than be fully deduced. */
4952 tree
4954 {
4955 /* This can only be true in a member template. */
4958 /* This can only be true for a parameter pack. */
4961 /* A type parm can't refer to another parm. */
4975 }
4977 /* Check that a template declaration's use of default arguments and
4978 parameter packs is not invalid. Here, PARMS are the template
4979 parameters. IS_PRIMARY is true if DECL is the thing declared by
4980 a primary template. IS_PARTIAL is true if DECL is a partial
4981 specialization.
4983 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
4984 function template declaration or a friend class template
4985 declaration. In the function case, 1 indicates a declaration, 2
4986 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
4987 emitted for extraneous default arguments.
4989 Returns TRUE if there were no errors found, FALSE otherwise. */
4991 bool
4994 {
4997 tree parm_level;
5000 /* [temp.param]
5002 A default template-argument shall not be specified in a
5003 function template declaration or a function template definition, nor
5004 in the template-parameter-list of the definition of a member of a
5005 class template. */
5009 /* You can't have a function template declaration in a local
5010 scope, nor you can you define a member of a class template in a
5011 local scope. */
5019 /* A lambda doesn't have an explicit declaration; don't complain
5020 about the parms of the enclosing class. */
5027 /* If this is either a friend defined in the scope of the class
5028 or a member function. */
5034 /* And, if it was a member function, it really was defined in
5035 the scope of the class. */
5038 /* We already checked these parameters when the template was
5039 declared, so there's no need to do it again now. This function
5040 was defined in class scope, but we're processing its body now
5041 that the class is complete. */
5044 /* Core issue 226 (C++0x only): the following only applies to class
5045 templates. */
5048 {
5049 /* [temp.param]
5051 If a template-parameter has a default template-argument, all
5052 subsequent template-parameters shall have a default
5053 template-argument supplied. */
5055 {
5062 {
5072 {
5074 /* For better subsequent error-recovery, we indicate that
5075 there should have been a default argument. */
5078 }
5080 && !is_friend_decl
5081 /* Don't complain about an enclosing partial
5082 specialization. */
5087 /* A fixed parameter pack will be partially
5088 instantiated into a fixed length list. */
5090 {
5091 /* A primary class template can only have one
5092 parameter pack, at the end of the template
5093 parameter list. */
5101 }
5102 }
5103 }
5104 }
5107 || is_partial
5108 || !is_primary
5110 /* For an ordinary class template, default template arguments are
5111 allowed at the innermost level, e.g.:
5112 template <class T = int>
5113 struct S {};
5114 but, in a partial specialization, they're not allowed even
5115 there, as we have in [temp.class.spec]:
5117 The template parameter list of a specialization shall not
5118 contain default template argument values.
5120 So, for a partial specialization, or for a function template
5121 (in C++98/C++03), we look at all of them. */
5122 ;
5123 else
5124 /* But, for a primary class template that is not a partial
5125 specialization we look at all template parameters except the
5126 innermost ones. */
5129 /* Figure out what error message to issue. */
5144 else
5145 /* Per [temp.param]/9, "A default template-argument shall not be
5146 specified in the template-parameter-lists of the definition of
5147 a member of a class template that appears outside of the member's
5148 class.", thus if we aren't handling a member of a class template
5149 there is no need to examine the parameters. */
5153 /* If we're inside a class definition, there's no need to
5154 examine the parameters to the class itself. On the one
5155 hand, they will be checked when the class is defined, and,
5156 on the other, default arguments are valid in things like:
5157 template <class T = double>
5158 struct S { template <class U> void f(U); };
5159 Here the default argument for `S' has no bearing on the
5160 declaration of `f'. */
5162 else
5163 /* Check everything. */
5169 {
5176 {
5181 {
5183 {
5190 }
5192 /* Clear out the default argument so that we are not
5193 confused later. */
5195 }
5196 }
5198 /* At this point, if we're still interested in issuing messages,
5199 they must apply to classes surrounding the object declared. */
5203 }
5206 }
5208 /* Worker for push_template_decl_real, called via
5209 for_each_template_parm. DATA is really an int, indicating the
5210 level of the parameters we are interested in. If T is a template
5211 parameter of that level, return nonzero. */
5213 static int
5215 {
5221 else
5224 }
5226 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5227 DATA is really an int, indicating the innermost outer level of parameters.
5228 If T is a template parameter of that level or further out, return
5229 nonzero. */
5231 static int
5233 {
5239 else
5242 }
5244 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5245 parameters given by current_template_args, or reuses a
5246 previously existing one, if appropriate. Returns the DECL, or an
5247 equivalent one, if it is replaced via a call to duplicate_decls.
5249 If IS_FRIEND is true, DECL is a friend declaration. */
5251 tree
5253 {
5254 tree tmpl;
5255 tree args;
5256 tree info;
5257 tree ctx;
5261 /* True if the template is a member template, in the sense of
5262 [temp.mem]. */
5268 /* See if this is a partial specialization. */
5281 /* For a friend, we want the context of the friend, not
5282 the type of which it is a friend. */
5286 /* In the case of a virtual function, we want the class in which
5287 it is defined. */
5289 else
5290 /* Otherwise, if we're currently defining some class, the DECL
5291 is assumed to be a member of the class. */
5300 /* See if this is a primary template. */
5303 /* A friend template that specifies a class context, i.e.
5304 template <typename T> friend void A<T>::f();
5305 is not primary. */
5310 else
5314 {
5321 {
5324 }
5326 {
5328 {
5331 }
5333 {
5334 /* [temp.mem]
5336 A destructor shall not be a member template. */
5339 }
5346 {
5347 /* [basic.stc.dynamic.allocation]
5349 An allocation function can be a function
5350 template. ... Template allocation functions shall
5351 have two or more parameters. */
5354 }
5355 }
5358 {
5359 /* Class template, set TEMPLATE_TYPE_PARM_FOR_CLASS. */
5362 {
5368 }
5369 }
5372 /* alias-declaration */
5376 else
5377 {
5380 }
5381 }
5383 /* Check to see that the rules regarding the use of default
5384 arguments are not being violated. We check args for a friend
5385 functions when we know whether it's a definition, introducing
5386 declaration or re-declaration. */
5391 /* Ensure that there are no parameter packs in the type of this
5392 declaration that have not been expanded. */
5394 {
5395 /* Check each of the arguments individually to see if there are
5396 any bare parameter packs. */
5402 {
5405 {
5406 /* This is a PARM_DECL that contains unexpanded parameter
5407 packs. We have already complained about this in the
5408 check_for_bare_parameter_packs call, so just replace
5409 these types with ERROR_MARK_NODE. */
5412 }
5416 }
5418 /* Check for bare parameter packs in the return type and the
5419 exception specifiers. */
5421 /* Errors were already issued, set return type to int
5422 as the frontend doesn't expect error_mark_node as
5423 the return type. */
5427 }
5432 {
5435 }
5448 {
5453 /* If DECL is a TYPE_DECL for a class-template, then there won't
5454 be DECL_LANG_SPECIFIC. The information equivalent to
5455 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
5459 {
5460 /* Since a template declaration already existed for this
5461 class-type, we must be redeclaring it here. Make sure
5462 that the redeclaration is valid. */
5464 current_template_parms,
5466 /* We don't need to create a new TEMPLATE_DECL; just use the
5467 one we already had. */
5469 }
5470 else
5471 {
5473 member_template_p);
5478 {
5479 /* A specialization of a member template of a template
5480 class. */
5484 }
5485 }
5486 }
5487 else
5488 {
5494 {
5497 }
5505 {
5506 tree new_tmpl;
5508 /* The declaration is a specialization of a member
5509 template, declared outside the class. Therefore, the
5510 innermost template arguments will be NULL, so we
5511 replace them with the arguments determined by the
5512 earlier call to check_explicit_specialization. */
5515 new_tmpl
5517 member_template_p);
5527 args,
5530 }
5532 /* Make sure the template headers we got make sense. */
5537 {
5542 }
5543 else
5545 {
5550 {
5554 else
5558 /* Avoid crash in import_export_decl. */
5561 }
5566 /* Can happen in erroneous input. */
5568 else
5570 }
5572 /* Check that the parms are used in the appropriate qualifying scopes
5573 in the declarator. */
5577 {
5583 /* Avoid crash in import_export_decl. */
5586 }
5587 }
5592 /* Push template declarations for global functions and types. Note
5593 that we do not try to push a global template friend declared in a
5594 template class; such a thing may well depend on the template
5595 parameters of the class. */
5598 {
5603 /* Hide template friend classes that haven't been declared yet. */
5605 {
5608 }
5609 }
5612 {
5617 /* Give template template parms a DECL_CONTEXT of the template
5618 for which they are a parameter. */
5621 {
5625 }
5631 }
5633 /* The DECL_TI_ARGS of DECL contains full set of arguments referring
5634 back to its most general template. If TMPL is a specialization,
5635 ARGS may only have the innermost set of arguments. Add the missing
5636 argument levels if necessary. */
5644 else
5645 {
5650 }
5653 && !is_friend
5656 /* Set DECL_COMDAT on template instantiations; if we force
5657 them to be emitted by explicit instantiation or -frepo,
5658 mark_needed will tell cgraph to do the right thing. */
5662 }
5664 tree
5666 {
5668 }
5670 /* FN is an inheriting constructor that inherits from the constructor
5671 template INHERITED; turn FN into a constructor template with a matching
5672 template header. */
5674 tree
5676 {
5677 tree inner_parms
5680 tree parms
5691 }
5693 /* Called when a class template TYPE is redeclared with the indicated
5694 template PARMS, e.g.:
5696 template <class T> struct S;
5697 template <class T> struct S {}; */
5699 bool
5701 {
5702 tree tmpl;
5703 tree tmpl_parms;
5707 {
5710 }
5714 /* The type is nested in some template class. Nothing to worry
5715 about here; there are no new template parameters for the nested
5716 type. */
5720 {
5722 tmpl);
5724 }
5730 {
5740 }
5743 {
5744 tree tmpl_parm;
5745 tree parm;
5746 tree tmpl_default;
5747 tree parm_default;
5761 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
5762 TEMPLATE_DECL. */
5772 {
5776 }
5779 {
5780 /* We have in [temp.param]:
5782 A template-parameter may not be given default arguments
5783 by two different declarations in the same scope. */
5788 }
5791 /* Update the previous template parameters (which are the ones
5792 that will really count) with the new default value. */
5795 /* Update the new parameters, too; they'll be used as the
5796 parameters for any members. */
5799 /* Give each template template parm in this redeclaration a
5800 DECL_CONTEXT of the template for which they are a parameter. */
5802 {
5805 }
5809 }
5811 // Cannot redeclare a class template with a different set of constraints.
5813 {
5818 }
5821 }
5823 /* The actual substitution part of instantiate_non_dependent_expr_sfinae,
5824 to be used when the caller has already checked
5825 (processing_template_decl
5826 && !instantiation_dependent_expression_p (expr)
5827 && potential_constant_expression (expr))
5828 and cleared processing_template_decl. */
5830 tree
5832 {
5835 complain,
5839 }
5841 /* Simplify EXPR if it is a non-dependent expression. Returns the
5842 (possibly simplified) expression. */
5844 tree
5846 {
5850 /* If we're in a template, but EXPR isn't value dependent, simplify
5851 it. We're supposed to treat:
5853 template <typename T> void f(T[1 + 1]);
5854 template <typename T> void f(T[2]);
5856 as two declarations of the same function, for example. */
5859 {
5860 processing_template_decl_sentinel s;
5862 }
5864 }
5866 tree
5868 {
5870 }
5872 /* Like instantiate_non_dependent_expr, but return NULL_TREE rather than
5873 an uninstantiated expression. */
5875 tree
5877 {
5881 {
5884 else
5885 {
5886 processing_template_decl_sentinel s;
5888 }
5889 }
5891 }
5893 /* True iff T is a specialization of a variable template. */
5895 bool
5897 {
5902 }
5904 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
5905 template declaration, or a TYPE_DECL for an alias declaration. */
5907 bool
5909 {
5917 }
5919 /* Return TRUE iff T is a specialization of an alias template. */
5921 bool
5923 {
5924 /* It's an alias template specialization if it's an alias and its
5925 TYPE_NAME is a specialization of a primary template. */
5931 }
5933 /* An alias template is complex from a SFINAE perspective if a template-id
5934 using that alias can be ill-formed when the expansion is not, as with
5935 the void_t template. We determine this by checking whether the
5936 expansion for the alias template uses all its template parameters. */
5938 struct uses_all_template_parms_data
5939 {
5942 };
5944 static int
5946 {
5954 }
5956 static bool
5958 {
5973 }
5975 /* Return TRUE iff T is a specialization of a complex alias template with
5976 dependent template-arguments. */
5978 bool
5980 {
5993 }
5995 /* Return the number of innermost template parameters in TMPL. */
5997 static int
5999 {
6002 }
6004 /* Return either TMPL or another template that it is equivalent to under DR
6005 1286: An alias that just changes the name of a template is equivalent to
6006 the other template. */
6008 static tree
6010 {
6013 {
6014 /* Determine if the alias is equivalent to an underlying template. */
6026 tree alias_args = INNERMOST_TEMPLATE_ARGS
6031 /* Alias is equivalent. Strip it and repeat. */
6033 }
6036 }
6038 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6039 must be a reference-to-function or a pointer-to-function type, as specified
6040 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6041 and check that the resulting function has external linkage. */
6043 static tree
6045 tsubst_flags_t complain)
6046 {
6049 linkage_kind linkage;
6064 /* [temp.arg.nontype]/1
6066 A template-argument for a non-type, non-template template-parameter
6067 shall be one of:
6068 [...]
6069 -- the address of an object or function with external [C++11: or
6070 internal] linkage. */
6073 {
6075 {
6081 else
6084 }
6086 }
6090 {
6092 {
6097 else
6101 }
6103 }
6105 accept:
6112 }
6114 /* Subroutine of convert_nontype_argument.
6115 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6116 Emit an error otherwise. */
6118 static bool
6120 tsubst_flags_t complain)
6121 {
6138 {
6143 else
6145 }
6147 }
6149 /* Returns TRUE iff the address of OP is value-dependent.
6151 14.6.2.4 [temp.dep.temp]:
6152 A non-integral non-type template-argument is dependent if its type is
6153 dependent or it has either of the following forms
6154 qualified-id
6155 & qualified-id
6156 and contains a nested-name-specifier which specifies a class-name that
6157 names a dependent type.
6159 We generalize this to just say that the address of a member of a
6160 dependent class is value-dependent; the above doesn't cover the
6161 address of a static data member named with an unqualified-id. */
6163 static bool
6165 {
6166 /* We could use get_inner_reference here, but there's no need;
6167 this is only relevant for template non-type arguments, which
6168 can only be expressed as &id-expression. */
6170 {
6174 }
6177 }
6179 /* The next set of functions are used for providing helpful explanatory
6180 diagnostics for failed overload resolution. Their messages should be
6181 indented by two spaces for consistency with the messages in
6182 call.c */
6184 static int
6186 {
6188 }
6190 /* Other failure functions should call this one, to provide a single function
6191 for setting a breakpoint on. */
6193 static int
6195 {
6197 }
6199 static int
6201 {
6206 }
6208 static int
6210 {
6216 }
6218 static int
6220 {
6224 }
6226 static int
6228 {
6231 " template parameter %qD is not a parameter pack, but "
6235 }
6237 static int
6239 {
6242 " template argument %qE does not match "
6246 }
6248 static int
6250 {
6254 }
6256 static int
6258 {
6264 }
6266 static int
6268 {
6270 {
6275 else
6277 " deduced conflicting values for non-type parameter "
6279 }
6281 }
6283 static int
6285 {
6288 " variable-sized array type %qT is not "
6290 arg);
6292 }
6294 static int
6296 {
6300 arg);
6302 }
6304 static int
6306 {
6308 {
6314 else
6319 }
6321 }
6323 static int
6325 {
6327 }
6329 static int
6332 {
6334 }
6336 static int
6339 {
6345 }
6347 static int
6350 {
6353 {
6361 }
6363 }
6365 static int
6367 {
6370 " template parameters of a template template argument are "
6373 }
6375 static int
6377 {
6383 }
6385 static int
6387 {
6392 }
6394 /* Attempt to convert the non-type template parameter EXPR to the
6395 indicated TYPE. If the conversion is successful, return the
6396 converted value. If the conversion is unsuccessful, return
6397 NULL_TREE if we issued an error message, or error_mark_node if we
6398 did not. We issue error messages for out-and-out bad template
6399 parameters, but not simply because the conversion failed, since we
6400 might be just trying to do argument deduction. Both TYPE and EXPR
6401 must be non-dependent.
6403 The conversion follows the special rules described in
6404 [temp.arg.nontype], and it is much more strict than an implicit
6405 conversion.
6407 This function is called twice for each template argument (see
6408 lookup_template_class for a more accurate description of this
6409 problem). This means that we need to handle expressions which
6410 are not valid in a C++ source, but can be created from the
6411 first call (for instance, casts to perform conversions). These
6412 hacks can go away after we fix the double coercion problem. */
6414 static tree
6416 {
6417 tree expr_type;
6421 /* Detect immediately string literals as invalid non-type argument.
6422 This special-case is not needed for correctness (we would easily
6423 catch this later), but only to provide better diagnostic for this
6424 common user mistake. As suggested by DR 100, we do not mention
6425 linkage issues in the diagnostic as this is not the point. */
6426 /* FIXME we're making this OK. */
6428 {
6434 }
6436 /* Add the ADDR_EXPR now for the benefit of
6437 value_dependent_expression_p. */
6440 {
6444 }
6446 /* If we are in a template, EXPR may be non-dependent, but still
6447 have a syntactic, rather than semantic, form. For example, EXPR
6448 might be a SCOPE_REF, rather than the VAR_DECL to which the
6449 SCOPE_REF refers. Preserving the qualifying scope is necessary
6450 so that access checking can be performed when the template is
6451 instantiated -- but here we need the resolved form so that we can
6452 convert the argument. */
6464 /* If the argument is non-dependent, perform any conversions in
6465 non-dependent context as well. */
6473 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
6474 to a non-type argument of "nullptr". */
6478 /* In C++11, integral or enumeration non-type template arguments can be
6479 arbitrary constant expressions. Pointer and pointer to
6480 member arguments can be general constant expressions that evaluate
6481 to a null value, but otherwise still need to be of a specific form. */
6483 {
6485 /* A PTRMEM_CST is already constant, and a valid template
6486 argument for a parameter of pointer to member type, we just want
6487 to leave it in that form rather than lower it to a
6491 {
6492 /* C++17: A template-argument for a non-type template-parameter shall
6493 be a converted constant expression (8.20) of the type of the
6494 template-parameter. */
6500 }
6502 {
6507 }
6508 }
6512 else
6515 /* HACK: Due to double coercion, we can get a
6516 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
6517 which is the tree that we built on the first call (see
6518 below when coercing to reference to object or to reference to
6519 function). We just strip everything and get to the arg.
6520 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
6521 for examples. */
6523 {
6529 {
6530 /* ??? Maybe we could use convert_from_reference here, but we
6531 would need to relax its constraints because the NOP_EXPR
6532 could actually change the type to something more cv-qualified,
6533 and this is not folded by convert_from_reference. */
6538 && (same_type_ignoring_top_level_qualifiers_p
6541 {
6544 }
6545 }
6546 }
6548 /* [temp.arg.nontype]/5, bullet 1
6550 For a non-type template-parameter of integral or enumeration type,
6551 integral promotions (_conv.prom_) and integral conversions
6552 (_conv.integral_) are applied. */
6554 {
6556 {
6561 }
6566 /* Notice that there are constant expressions like '4 % 0' which
6567 do not fold into integer constants. */
6570 {
6572 {
6576 else
6582 /* else cxx_constant_value complained but gave us
6583 a real constant, so go ahead. */
6585 {
6586 /* Some assemble time constant expressions like
6587 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
6588 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
6589 as we can emit them into .rodata initializers of
6590 variables, yet they can't fold into an INTEGER_CST at
6591 compile time. Refuse them here. */
6596 }
6597 }
6598 else
6600 }
6602 /* Avoid typedef problems. */
6605 }
6606 /* [temp.arg.nontype]/5, bullet 2
6608 For a non-type template-parameter of type pointer to object,
6609 qualification conversions (_conv.qual_) and the array-to-pointer
6610 conversion (_conv.array_) are applied. */
6612 {
6615 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
6616 decay_conversion or an explicit cast. If it's a problematic cast,
6617 we'll complain about it below. */
6619 {
6624 {
6627 }
6628 }
6630 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
6632 A template-argument for a non-type, non-template template-parameter
6633 shall be one of: [...]
6635 -- the name of a non-type template-parameter;
6636 -- the address of an object or function with external linkage, [...]
6637 expressed as "& id-expression" where the & is optional if the name
6638 refers to a function or array, or if the corresponding
6639 template-parameter is a reference.
6641 Here, we do not care about functions, as they are invalid anyway
6642 for a parameter of type pointer-to-object. */
6645 /* Non-type template parameters are OK. */
6646 ;
6650 {
6652 {
6655 "because %qD is a variable, not the address of "
6658 }
6660 {
6666 }
6667 /* Other values, like integer constants, might be valid
6668 non-type arguments of some other type. */
6670 }
6671 else
6672 {
6676 {
6681 }
6683 {
6689 }
6692 {
6697 }
6698 /* C++17: For a non-type template-parameter of reference or pointer
6699 type, the value of the constant expression shall not refer to (or
6700 for a pointer type, shall not be the address of):
6701 * a subobject (4.5),
6702 * a temporary object (15.2),
6703 * a string literal (5.13.5),
6704 * the result of a typeid expression (8.2.8), or
6705 * a predefined __func__ variable (11.4.1). */
6707 {
6710 decl);
6712 }
6716 {
6721 }
6723 {
6727 decl);
6729 }
6730 }
6737 }
6738 /* [temp.arg.nontype]/5, bullet 3
6740 For a non-type template-parameter of type reference to object, no
6741 conversions apply. The type referred to by the reference may be more
6742 cv-qualified than the (otherwise identical) type of the
6743 template-argument. The template-parameter is bound directly to the
6744 template-argument, which must be an lvalue. */
6746 {
6748 expr_type))
6752 {
6757 }
6760 {
6765 }
6767 /* [temp.arg.nontype]/1
6769 A template-argument for a non-type, non-template template-parameter
6770 shall be one of: [...]
6772 -- the address of an object or function with external linkage. */
6775 {
6778 {
6781 "because a reference variable does not have a constant "
6784 }
6785 }
6789 /* OK, dependent reference. We don't want to ask whether a DECL is
6791 else
6792 {
6794 {
6800 }
6802 /* DR 1155 allows internal linkage in C++11 and up. */
6805 {
6811 }
6814 }
6818 }
6819 /* [temp.arg.nontype]/5, bullet 4
6821 For a non-type template-parameter of type pointer to function, only
6822 the function-to-pointer conversion (_conv.func_) is applied. If the
6823 template-argument represents a set of overloaded functions (or a
6824 pointer to such), the matching function is selected from the set
6825 (_over.over_). */
6827 {
6828 /* If the argument is a template-id, we might not have enough
6829 context information to decay the pointer. */
6831 {
6835 }
6838 /* Null pointer values are OK in C++11. */
6844 }
6845 /* [temp.arg.nontype]/5, bullet 5
6847 For a non-type template-parameter of type reference to function, no
6848 conversions apply. If the template-argument represents a set of
6849 overloaded functions, the matching function is selected from the set
6850 (_over.over_). */
6852 {
6854 {
6856 {
6861 }
6863 }
6868 }
6869 /* [temp.arg.nontype]/5, bullet 6
6871 For a non-type template-parameter of type pointer to member function,
6872 no conversions apply. If the template-argument represents a set of
6873 overloaded member functions, the matching member function is selected
6874 from the set (_over.over_). */
6876 {
6881 /* [temp.arg.nontype] bullet 1 says the pointer to member
6882 expression must be a pointer-to-member constant. */
6887 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
6888 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
6891 }
6892 /* [temp.arg.nontype]/5, bullet 7
6894 For a non-type template-parameter of type pointer to data member,
6895 qualification conversions (_conv.qual_) are applied. */
6897 {
6898 /* [temp.arg.nontype] bullet 1 says the pointer to member
6899 expression must be a pointer-to-member constant. */
6907 }
6909 {
6911 {
6916 }
6918 }
6919 /* A template non-type parameter must be one of the above. */
6920 else
6923 /* Sanity check: did we actually convert the argument to the
6924 right type? */
6928 }
6930 /* Subroutine of coerce_template_template_parms, which returns 1 if
6931 PARM_PARM and ARG_PARM match using the rule for the template
6932 parameters of template template parameters. Both PARM and ARG are
6933 template parameters; the rest of the arguments are the same as for
6934 coerce_template_template_parms.
6935 */
6936 static int
6938 tree arg,
6939 tsubst_flags_t complain,
6940 tree in_decl,
6941 tree outer_args)
6942 {
6951 {
6953 /* We encounter instantiations of templates like
6954 template <template <template <class> class> class TT>
6955 class C; */
6956 {
6963 }
6964 /* Fall through. */
6969 /* Argument is a parameter pack but parameter is not. */
6974 /* The tsubst call is used to handle cases such as
6976 template <int> class C {};
6977 template <class T, template <T> class TT> class D {};
6978 D<int, C> d;
6980 i.e. the parameter list of TT depends on earlier parameters. */
6982 {
6987 }
6991 /* Argument is a parameter pack but parameter is not. */
6998 }
7001 }
7003 /* Coerce template argument list ARGLIST for use with template
7004 template-parameter TEMPL. */
7006 static tree
7008 tsubst_flags_t complain)
7009 {
7010 /* Consider an example where a template template parameter declared as
7012 template <class T, class U = std::allocator<T> > class TT
7014 The template parameter level of T and U are one level larger than
7015 of TT. To proper process the default argument of U, say when an
7016 instantiation `TT<int>' is seen, we need to build the full
7017 arguments containing {int} as the innermost level. Outer levels,
7018 available when not appearing as default template argument, can be
7019 obtained from the arguments of the enclosing template.
7021 Suppose that TT is later substituted with std::vector. The above
7022 instantiation is `TT<int, std::allocator<T> >' with TT at
7023 level 1, and T at level 2, while the template arguments at level 1
7024 becomes {std::vector} and the inner level 2 is {int}. */
7028 {
7030 /* We want arguments for the partial specialization, not arguments for
7031 the primary template. */
7033 else
7035 }
7037 {
7038 /* This is an argument of the current template, so we haven't set
7039 DECL_CONTEXT yet. */
7040 tree relevant_template_parms;
7042 /* Parameter levels that are greater than the level of the given
7043 template template parm are irrelevant. */
7050 }
7057 complain,
7060 }
7062 /* A cache of template template parameters with match-all default
7063 arguments. */
7065 static void
7067 {
7071 }
7072 static tree
7074 {
7079 }
7081 /* T is a bound template template-parameter. Copy its arguments into default
7082 arguments of the template template-parameter's template parameters. */
7084 static tree
7086 {
7109 {
7112 {
7115 }
7116 }
7120 }
7122 /* ARG is a bound potential template template-argument, and PARGS is a list
7123 of arguments for the corresponding template template-parameter. Adjust
7124 PARGS as appropriate for application to ARG's template, and if ARG is a
7125 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
7126 arguments to the template template parameter. */
7128 static tree
7130 {
7134 {
7135 /* When comparing two template template-parameters in partial ordering,
7136 rewrite the one currently being used as an argument to have default
7137 arguments for all parameters. */
7143 }
7144 else
7145 {
7146 tree aparms
7151 }
7154 }
7156 /* Subroutine of unify for the case when PARM is a
7157 BOUND_TEMPLATE_TEMPLATE_PARM. */
7159 static int
7162 {
7166 /* The template template parm might be variadic and the argument
7167 not, so flatten both argument lists. */
7172 {
7173 /* In keeping with P0522R0, adjust P's template arguments
7174 to apply to A's template; then flatten it again. */
7183 /* If the P0522 adjustment eliminated a pack expansion, deduce
7184 empty packs. */
7190 }
7191 else
7192 {
7193 /* Deduce arguments T, i from TT<T> or TT<i>.
7194 We check each element of PARMVEC and ARGVEC individually
7195 rather than the whole TREE_VEC since they can have
7196 different number of elements, which is allowed under N2555. */
7200 /* Check if the parameters end in a pack, making them
7201 variadic. */
7208 /* If the template argument list of P contains a pack
7209 expansion that is not the last template argument, the
7210 entire template argument list is a non-deduced
7211 context. */
7229 DEDUCE_EXACT,
7232 }
7235 }
7237 /* Return 1 if PARM_PARMS and ARG_PARMS matches using rule for
7238 template template parameters. Both PARM_PARMS and ARG_PARMS are
7239 vectors of TREE_LIST nodes containing TYPE_DECL, TEMPLATE_DECL
7240 or PARM_DECL.
7242 Consider the example:
7243 template <class T> class A;
7244 template<template <class U> class TT> class B;
7246 For B<A>, PARM_PARMS are the parameters to TT, while ARG_PARMS are
7247 the parameters to A, and OUTER_ARGS contains A. */
7249 static int
7251 tree arg_parms,
7252 tsubst_flags_t complain,
7253 tree in_decl,
7254 tree outer_args)
7255 {
7267 {
7268 /* P0522R0: A template template-parameter P is at least as specialized as
7269 a template template-argument A if, given the following rewrite to two
7270 function templates, the function template corresponding to P is at
7271 least as specialized as the function template corresponding to A
7272 according to the partial ordering rules for function templates
7273 ([temp.func.order]). Given an invented class template X with the
7274 template parameter list of A (including default arguments):
7276 * Each of the two function templates has the same template parameters,
7277 respectively, as P or A.
7279 * Each function template has a single function parameter whose type is
7280 a specialization of X with template arguments corresponding to the
7281 template parameters from the respective function template where, for
7282 each template parameter PP in the template parameter list of the
7283 function template, a corresponding template argument AA is formed. If
7284 PP declares a parameter pack, then AA is the pack expansion
7285 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
7287 If the rewrite produces an invalid type, then P is not at least as
7288 specialized as A. */
7290 /* So coerce P's args to apply to A's parms, and then deduce between A's
7291 args and the converted args. If that succeeds, A is at least as
7292 specialized as P, so they match.*/
7299 {
7305 }
7306 }
7308 /* Determine whether we have a parameter pack at the end of the
7309 template template parameter's template parameter list. */
7311 {
7318 {
7332 }
7333 }
7339 /* Check all of the template parameters except the parameter pack at
7340 the end (if any). */
7342 {
7351 outer_args))
7354 }
7357 {
7358 /* Check each of the template parameters in the template
7359 argument against the template parameter pack at the end of
7360 the template template parameter. */
7367 {
7374 outer_args))
7376 }
7377 }
7380 }
7382 /* Verifies that the deduced template arguments (in TARGS) for the
7383 template template parameters (in TPARMS) represent valid bindings,
7384 by comparing the template parameter list of each template argument
7385 to the template parameter list of its corresponding template
7386 template parameter, in accordance with DR150. This
7387 routine can only be called after all template arguments have been
7388 deduced. It will return TRUE if all of the template template
7389 parameter bindings are okay, FALSE otherwise. */
7390 bool
7392 {
7396 /* We're dealing with template parms in this process. */
7402 {
7407 {
7412 {
7413 /* Look inside the argument pack. */
7416 }
7419 {
7423 /* Extract the next argument from the argument
7424 pack. */
7428 /* Look at the pattern of the pack expansion. */
7431 /* Extract the template parameters from the template
7432 argument. */
7438 /* Verify that we can coerce the template template
7439 parameters from the template argument to the template
7440 parameter. This requires an exact match. */
7442 && !coerce_template_template_parms
7444 targ_parms,
7445 tf_none,
7446 tparm,
7447 targs))
7448 {
7451 }
7452 }
7453 }
7454 }
7456 out:
7460 }
7462 /* Since type attributes aren't mangled, we need to strip them from
7463 template type arguments. */
7465 static tree
7467 {
7477 }
7479 /* And from inside dependent non-type arguments like sizeof(Type). */
7481 static tree
7483 {
7493 }
7495 // A template declaration can be substituted for a constrained
7496 // template template parameter only when the argument is more
7497 // constrained than the parameter.
7498 static bool
7500 {
7503 /* For now, allow constrained template template arguments
7504 and unconstrained template template parameters. */
7510 // If the template parameter is constrained, we need to rewrite its
7511 // constraints in terms of the ARG's template parameters. This ensures
7512 // that all of the template parameter types will have the same depth.
7513 //
7514 // Note that this is only valid when coerce_template_template_parm is
7515 // true for the innermost template parameters of PARM and ARG. In other
7516 // words, because coercion is successful, this conversion will be valid.
7518 {
7525 }
7528 }
7530 // Convert a placeholder argument into a binding to the original
7531 // parameter. The original parameter is saved as the TREE_TYPE of
7532 // ARG.
7535 {
7538 }
7540 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
7541 because one of them is dependent. But we need to represent the
7542 conversion for the benefit of cp_tree_equal. */
7544 static tree
7546 {
7547 /* Auto parms get no conversion. */
7550 /* We don't need or want to add this conversion now if we're going to use the
7551 argument for deduction. */
7563 }
7565 /* Convert the indicated template ARG as necessary to match the
7566 indicated template PARM. Returns the converted ARG, or
7567 error_mark_node if the conversion was unsuccessful. Error and
7568 warning messages are issued under control of COMPLAIN. This
7569 conversion is for the Ith parameter in the parameter list. ARGS is
7570 the full set of template arguments deduced so far. */
7572 static tree
7574 tree arg,
7575 tree args,
7576 tsubst_flags_t complain,
7578 tree in_decl)
7579 {
7580 tree orig_arg;
7581 tree val;
7587 /* Trivially convert placeholders. */
7596 {
7597 /* The template argument was the name of some
7598 member function. That's usually
7599 invalid, but static members are OK. In any
7600 case, grab the underlying fields/functions
7601 and issue an error later if required. */
7604 }
7612 /* When determining whether an argument pack expansion is a template,
7613 look at the pattern. */
7617 /* Deal with an injected-class-name used as a template template arg. */
7619 {
7622 {
7632 }
7633 }
7635 is_tmpl_type =
7651 {
7653 {
7657 }
7660 "to refer to a type member of a template parameter, "
7665 typename_type,
7666 complain);
7669 }
7671 {
7673 {
7675 {
7687 else
7690 }
7691 }
7693 }
7695 {
7697 {
7704 else
7707 }
7709 }
7712 /* We already did the appropriate conversion when packing args. */
7715 {
7717 {
7719 /* The number of argument required is not known yet.
7720 Just accept it for now. */
7722 else
7723 {
7725 tree argparm;
7727 /* Strip alias templates that are equivalent to another
7728 template. */
7734 args))
7735 {
7738 /* TEMPLATE_TEMPLATE_PARM node is preferred over
7739 TEMPLATE_DECL. */
7741 {
7746 }
7747 }
7748 else
7749 {
7751 {
7758 }
7761 }
7763 // Check that the constraints are compatible before allowing the
7764 // substitution.
7767 {
7769 {
7775 }
7777 }
7778 }
7779 }
7780 else
7782 /* We only form one instance of each template specialization.
7783 Therefore, if we use a non-canonical variant (i.e., a
7784 typedef), any future messages referring to the type will use
7785 the typedef, which is confusing if those future uses do not
7786 themselves also use the typedef. */
7789 }
7790 else
7791 {
7795 {
7799 }
7800 else
7808 /* We used to call digest_init here. However, digest_init
7809 will report errors, which we don't want when complain
7810 is zero. More importantly, digest_init will try too
7811 hard to convert things: for example, `0' should not be
7812 converted to pointer type at this point according to
7813 the standard. Accepting this is not merely an
7814 extension, since deciding whether or not these
7815 conversions can occur is part of determining which
7816 function template to call, or whether a given explicit
7817 argument specification is valid. */
7819 else
7820 {
7823 }
7833 {
7834 /* Reject template arguments that are references to built-in
7835 functions with no library fallbacks. */
7844 }
7847 {
7848 /* Strip typedefs from the SCOPE_REF. */
7851 complain);
7854 }
7855 }
7858 }
7860 /* Coerces the remaining template arguments in INNER_ARGS (from
7861 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
7862 Returns the coerced argument pack. PARM_IDX is the position of this
7863 parameter in the template parameter list. ARGS is the original
7864 template argument list. */
7865 static tree
7868 tree args,
7869 tree inner_args,
7871 tree new_args,
7873 tree in_decl,
7874 tsubst_flags_t complain)
7875 {
7878 tree packed_args;
7879 tree argument_pack;
7886 {
7887 /* When the template parameter is a non-type template parameter pack
7888 or template template parameter pack whose type or template
7889 parameters use parameter packs, we know exactly how many arguments
7890 we are looking for. Build a vector of the instantiated decls for
7891 these template parameters in PACKED_PARMS. */
7892 /* We can't use make_pack_expansion here because it would interpret a
7893 _DECL as a use rather than a declaration. */
7907 /* If we're doing a partial instantiation of a member template,
7908 verify that all of the types used for the non-type
7909 template parameter pack are, in fact, valid for non-type
7910 template parameters. */
7913 {
7916 {
7920 }
7921 /* We don't know how many args we have yet, just
7922 use the unconverted ones for now. */
7924 }
7927 }
7928 /* Check if we have a placeholder pack, which indicates we're
7929 in the context of a introduction list. In that case we want
7930 to match this pack to the single placeholder. */
7934 {
7937 }
7938 else
7941 /* Convert the remaining arguments, which will be a part of the
7942 parameter pack "parm". */
7945 {
7951 {
7952 /* Once we've packed as many args as we have types, stop. */
7956 /* We don't know how many args we have yet, just
7957 use the unconverted ones for now. */
7959 else
7961 }
7964 {
7967 }
7968 else
7971 in_decl);
7975 }
7979 {
7984 }
7989 else
7990 {
7993 }
8000 }
8002 /* Returns the number of pack expansions in the template argument vector
8003 ARGS. */
8005 static int
8007 {
8012 {
8016 }
8018 }
8020 /* Convert all template arguments to their appropriate types, and
8021 return a vector containing the innermost resulting template
8022 arguments. If any error occurs, return error_mark_node. Error and
8023 warning messages are issued under control of COMPLAIN.
8025 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
8026 for arguments not specified in ARGS. Otherwise, if
8027 USE_DEFAULT_ARGS is true, default arguments will be used to fill in
8028 unspecified arguments. If REQUIRE_ALL_ARGS is true, but
8029 USE_DEFAULT_ARGS is false, then all arguments must be specified in
8030 ARGS. */
8032 static tree
8034 tree args,
8035 tree in_decl,
8036 tsubst_flags_t complain,
8039 {
8041 tree orig_inner_args;
8042 tree inner_args;
8043 tree new_args;
8044 tree new_inner_args;
8048 /* When used as a boolean value, indicates whether this is a
8049 variadic template parameter list. Since it's an int, we can also
8050 subtract it from nparms to get the number of non-variadic
8051 parameters. */
8056 /* Likewise for parameters with default arguments. */
8064 /* Determine if there are any parameter packs or default arguments. */
8066 {
8074 }
8077 /* If there are no parameters that follow a parameter pack, we need to
8078 expand any argument packs so that we can deduce a parameter pack from
8079 some non-packed args followed by an argument pack, as in variadic85.C.
8080 If there are such parameters, we need to leave argument packs intact
8081 so the arguments are assigned properly. This can happen when dealing
8082 with a nested class inside a partial specialization of a class
8083 template, as in variadic92.C, or when deducing a template parameter pack
8084 from a sub-declarator, as in variadic114.C. */
8088 /* Count any pack expansion args. */
8094 && require_all_args
8095 && !variadic_args_p
8096 && (!use_default_args
8099 {
8101 {
8103 {
8107 }
8108 else
8115 }
8118 }
8119 /* We can't pass a pack expansion to a non-pack parameter of an alias
8120 template (DR 1430). */
8124 && variadic_args_p
8126 {
8128 {
8130 {
8136 {
8139 "pack expansion argument for non-pack parameter "
8141 else
8143 "pack expansion argument for non-pack parameter "
8147 }
8148 }
8150 found:;
8151 }
8153 }
8155 /* We need to evaluate the template arguments, even though this
8156 template-id may be nested within a "sizeof". */
8165 {
8166 tree arg;
8167 tree parm;
8169 /* Get the Ith template parameter. */
8173 {
8176 }
8178 /* Calculate the next argument. */
8181 else
8186 {
8187 /* Some arguments will be placed in the
8188 template parameter pack PARM. */
8195 {
8196 /* We don't know how many args we have yet, just use the
8197 unconverted (and still packed) ones for now. */
8201 }
8205 /* Store this argument. */
8207 {
8208 lost++;
8209 /* We are done with all of the arguments. */
8211 }
8212 else
8213 {
8216 }
8219 }
8221 {
8223 {
8224 /* "If every valid specialization of a variadic template
8225 requires an empty template parameter pack, the template is
8226 ill-formed, no diagnostic required." So check that the
8227 pattern works with this parameter. */
8232 in_decl);
8234 {
8239 }
8241 /* Recover from missing typename. */
8245 /* We don't know how many args we have yet, just
8246 use the unconverted ones for now. */
8250 }
8251 }
8253 {
8254 /* There must be a default arg in this case. */
8257 /* The position of the first default template argument,
8258 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
8259 Record that. */
8263 }
8264 else
8268 {
8271 }
8273 /* This only occurs if there was an error in the template
8274 parameter list itself (which we would already have
8275 reported) that we are trying to recover from, e.g., a class
8276 template with a parameter list such as
8277 template<typename..., typename>. */
8279 else
8285 lost++;
8287 }
8292 {
8294 {
8299 }
8301 }
8311 }
8313 /* Convert all template arguments to their appropriate types, and
8314 return a vector containing the innermost resulting template
8315 arguments. If any error occurs, return error_mark_node. Error and
8316 warning messages are not issued.
8318 Note that no function argument deduction is performed, and default
8319 arguments are used to fill in unspecified arguments. */
8320 tree
8322 {
8324 }
8326 /* Convert all template arguments to their appropriate type, and
8327 instantiate default arguments as needed. This returns a vector
8328 containing the innermost resulting template arguments, or
8329 error_mark_node if unsuccessful. */
8330 tree
8332 tsubst_flags_t complain)
8333 {
8335 }
8337 /* Like coerce_template_parms. If PARMS represents all template
8338 parameters levels, this function returns a vector of vectors
8339 representing all the resulting argument levels. Note that in this
8340 case, only the innermost arguments are coerced because the
8341 outermost ones are supposed to have been coerced already.
8343 Otherwise, if PARMS represents only (the innermost) vector of
8344 parameters, this function returns a vector containing just the
8345 innermost resulting arguments. */
8347 static tree
8349 tree args,
8350 tree in_decl,
8351 tsubst_flags_t complain,
8354 {
8357 tree coerced_args;
8360 {
8362 tree level;
8368 {
8369 tree l;
8373 require_all_args,
8374 use_default_args);
8375 else
8382 }
8383 }
8384 else
8387 require_all_args,
8388 use_default_args);
8390 }
8392 /* Returns 1 if template args OT and NT are equivalent. */
8394 int
8396 {
8405 /* For member templates */
8414 {
8431 }
8435 {
8438 /* Don't treat an alias template specialization with dependent
8439 arguments as equivalent to its underlying type when used as a
8440 template argument; we need them to be distinct so that we
8441 substitute into the specialization arguments at instantiation
8442 time. And aliases can't be equivalent without being ==, so
8443 we don't need to look any deeper.
8445 During partial ordering, however, we need to treat them normally so
8446 that we can order uses of the same alias with different
8447 cv-qualification (79960). */
8451 else
8453 }
8456 else
8457 {
8458 /* Try to treat a template non-type argument that has been converted
8459 to the parameter type as equivalent to one that hasn't yet. */
8472 }
8473 }
8475 /* Returns 1 iff the OLDARGS and NEWARGS are in fact identical sets of
8476 template arguments. Returns 0 otherwise, and updates OLDARG_PTR and
8477 NEWARG_PTR with the offending arguments if they are non-NULL. */
8479 int
8483 {
8496 {
8501 {
8507 }
8508 }
8510 }
8514 {
8516 }
8518 static void
8520 {
8530 /* We are called both from instantiate_decl, where we've already had a
8531 tinst_level pushed, and instantiate_template, where we haven't.
8532 Compensate. */
8543 else
8552 }
8555 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
8556 ARGLIST. Valid choices for FNS are given in the cp-tree.def
8557 documentation for TEMPLATE_ID_EXPR. */
8559 tree
8561 {
8562 tree type;
8570 {
8573 }
8576 {
8578 unknown_type_node,
8580 arglist);
8582 }
8589 }
8591 /* Within the scope of a template class S<T>, the name S gets bound
8592 (in build_self_reference) to a TYPE_DECL for the class, not a
8593 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
8594 or one of its enclosing classes, and that type is a template,
8595 return the associated TEMPLATE_DECL. Otherwise, the original
8596 DECL is returned.
8598 Also handle the case when DECL is a TREE_LIST of ambiguous
8599 injected-class-names from different bases. */
8601 tree
8603 {
8607 /* DR 176: A lookup that finds an injected-class-name (10.2
8608 [class.member.lookup]) can result in an ambiguity in certain cases
8609 (for example, if it is found in more than one base class). If all of
8610 the injected-class-names that are found refer to specializations of
8611 the same class template, and if the name is followed by a
8612 template-argument-list, the reference refers to the class template
8613 itself and not a specialization thereof, and is not ambiguous. */
8615 {
8618 {
8624 }
8627 else
8629 }
8635 }
8637 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
8638 parameters, find the desired type.
8640 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
8642 IN_DECL, if non-NULL, is the template declaration we are trying to
8643 instantiate.
8645 If ENTERING_SCOPE is nonzero, we are about to enter the scope of
8646 the class we are looking up.
8648 Issue error and warning messages under control of COMPLAIN.
8650 If the template class is really a local class in a template
8651 function, then the FUNCTION_CONTEXT is the function in which it is
8652 being instantiated.
8654 ??? Note that this function is currently called *twice* for each
8655 template-id: the first time from the parser, while creating the
8656 incomplete type (finish_template_type), and the second type during the
8657 real instantiation (instantiate_template_class). This is surely something
8658 that we want to avoid. It also causes some problems with argument
8659 coercion (see convert_nontype_argument for more information on this). */
8661 static tree
8664 {
8666 tree t;
8669 spec_entry elt;
8670 hashval_t hash;
8673 {
8677 else
8678 {
8685 }
8688 }
8690 {
8693 /* If we are declaring a constructor, say A<T>::A<T>, we will get
8694 an implicit typename for the second A. Deal with it. */
8699 {
8702 }
8703 }
8706 {
8709 }
8711 {
8715 }
8717 {
8720 }
8722 /* Issue an error message if we didn't find a template. */
8724 {
8728 }
8731 /* Make sure it's a user visible template, if it was named by
8732 the user. */
8735 {
8737 {
8741 }
8743 }
8747 /* An alias that just changes the name of a template is equivalent to the
8748 other template, so if any of the arguments are pack expansions, strip
8749 the alias to avoid problems with a pack expansion passed to a non-pack
8750 alias template parameter (DR 1430). */
8755 {
8756 tree parm;
8765 }
8766 else
8767 {
8769 tree gen_tmpl;
8770 tree type_decl;
8778 /* An error occurred while building the template TEMPL, and a
8779 diagnostic has most certainly been emitted for that
8780 already. Let's propagate that error. */
8789 {
8790 /* We've been given an incomplete set of template arguments.
8791 For example, given:
8793 template <class T> struct S1 {
8794 template <class U> struct S2 {};
8795 template <class U> struct S2<U*> {};
8796 };
8798 we will be called with an ARGLIST of `U*', but the
8799 TEMPLATE will be `template <class T> template
8800 <class U> struct S1<T>::S2'. We must fill in the missing
8801 arguments. */
8805 }
8807 /* Now we should have enough arguments. */
8810 /* From here on, we're only interested in the most general
8811 template. */
8813 /* Calculate the BOUND_ARGS. These will be the args that are
8814 actually tsubst'd into the definition to create the
8815 instantiation. */
8817 complain,
8822 /* We were unable to bind the arguments. */
8825 /* In the scope of a template class, explicit references to the
8826 template class refer to the type of the template, not any
8827 instantiation of it. For example, in:
8829 template <class T> class C { void f(C<T>); }
8831 the `C<T>' is just the same as `C'. Outside of the
8832 class, however, such a reference is an instantiation. */
8836 {
8841 }
8843 /* If we already have this specialization, return it. */
8853 /* If the the template's constraints are not satisfied,
8854 then we cannot form a valid type.
8856 Note that the check is deferred until after the hash
8857 lookup. This prevents redundant checks on previously
8858 instantiated specializations. */
8860 {
8862 {
8865 }
8867 }
8871 /* If the deduced arguments are invalid, then the binding
8872 failed. */
8876 complain))
8883 {
8888 }
8898 /* Create the type. */
8900 {
8901 /* The user referred to a specialization of an alias
8902 template represented by GEN_TMPL.
8904 [temp.alias]/2 says:
8906 When a template-id refers to the specialization of an
8907 alias template, it is equivalent to the associated
8908 type obtained by substitution of its
8909 template-arguments for the template-parameters in the
8910 type-id of the alias template. */
8913 /* Note that the call above (by indirectly calling
8914 register_specialization in tsubst_decl) registers the
8915 TYPE_DECL representing the specialization of the alias
8916 template. So next time someone substitutes ARGLIST for
8917 the template parms into the alias template (GEN_TMPL),
8918 she'll get that TYPE_DECL back. */
8922 }
8924 {
8926 {
8937 }
8938 else
8939 {
8940 /* We don't want to call start_enum for this type, since
8941 the values for the enumeration constants may involve
8942 template parameters. And, no one should be interested
8943 in the enumeration constants for such a type. */
8946 }
8950 }
8952 {
8958 /* A local class. Make sure the decl gets registered properly. */
8963 /* This instantiation is another name for the primary
8964 template type. Set the TYPE_CANONICAL field
8965 appropriately. */
8968 /* Some of the template arguments require structural
8969 equality testing, so this template class requires
8970 structural equality testing. */
8972 }
8973 else
8976 /* If we called start_enum or pushtag above, this information
8977 will already be set up. */
8979 {
8986 }
8987 else
8991 {
8997 {
9000 }
9001 }
9005 {
9009 {
9010 tree attributes
9018 }
9019 }
9021 /* Let's consider the explicit specialization of a member
9022 of a class template specialization that is implicitly instantiated,
9023 e.g.:
9024 template<class T>
9025 struct S
9026 {
9027 template<class U> struct M {}; //#0
9028 };
9030 template<>
9031 template<>
9032 struct S<int>::M<char> //#1
9033 {
9034 int i;
9035 };
9036 [temp.expl.spec]/4 says this is valid.
9038 In this case, when we write:
9039 S<int>::M<char> m;
9041 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
9042 the one of #0.
9044 When we encounter #1, we want to store the partial instantiation
9045 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
9047 For all cases other than this "explicit specialization of member of a
9048 class template", we just want to store the most general template into
9049 the CLASSTYPE_TI_TEMPLATE of M.
9051 This case of "explicit specialization of member of a class template"
9052 only happens when:
9053 1/ the enclosing class is an instantiation of, and therefore not
9054 the same as, the context of the most general template, and
9055 2/ we aren't looking at the partial instantiation itself, i.e.
9056 the innermost arguments are not the same as the innermost parms of
9057 the most general template.
9059 So it's only when 1/ and 2/ happens that we want to use the partial
9060 instantiation of the member template in lieu of its most general
9061 template. */
9065 /* the enclosing class must be an instantiation... */
9068 {
9072 tree partial_inst_args =
9079 use_partial_inst_tmpl =
9080 /*...and we must not be looking at the partial instantiation
9081 itself. */
9083 partial_inst_args);
9084 }
9087 /* This case is easy; there are no member templates involved. */
9089 else
9090 {
9091 /* This is a full instantiation of a member template. Find
9092 the partial instantiation of which this is an instance. */
9094 /* Temporarily reduce by one the number of levels in the ARGLIST
9095 so as to avoid comparing the last set of arguments. */
9099 /* FOUND is either a proper class type, or an alias
9100 template specialization. In the later case, it's a
9101 TYPE_DECL, resulting from the substituting of arguments
9102 for parameters in the TYPE_DECL of the alias template
9103 done earlier. So be careful while getting the template
9104 of FOUND. */
9106 ? found
9110 }
9112 // Build template info for the new specialization.
9121 /* Note this use of the partial instantiation so we can check it
9122 later in maybe_process_partial_specialization. */
9129 /* Now that the type has been registered on the instantiations
9130 list, we set up the enumerators. Because the enumeration
9131 constants may involve the enumeration type itself, we make
9132 sure to register the type first, and then create the
9133 constants. That way, doing tsubst_expr for the enumeration
9134 constants won't result in recursive calls here; we'll find
9135 the instantiation and exit above. */
9139 /* If the type makes use of template parameters, the
9140 code that generates debugging information will crash. */
9143 /* Possibly limit visibility based on template args. */
9150 }
9151 }
9153 /* Wrapper for lookup_template_class_1. */
9155 tree
9158 {
9159 tree ret;
9165 }
9167 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
9169 tree
9171 {
9172 /* The type of the expression is NULL_TREE since the template-id could refer
9173 to an explicit or partial specialization. */
9176 /* Except that concepts are always bool. */
9179 }
9181 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR for use. */
9183 tree
9185 {
9189 /* We never want to return a VAR_DECL for a variable concept, since they
9190 aren't instantiated. In a template, leave the TEMPLATE_ID_EXPR alone. */
9205 {
9207 {
9210 }
9212 }
9214 /* If a template-id refers to a specialization of a variable
9215 concept, then the expression is true if and only if the
9216 concept's constraints are satisfied by the given template
9217 arguments.
9219 NOTE: This is an extension of Concepts Lite TS that
9220 allows constraints to be used in expressions. */
9222 {
9225 }
9228 }
9230 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
9231 TARGS template args, and instantiate it if it's not dependent. */
9233 tree
9235 tsubst_flags_t complain)
9236 {
9239 {
9242 }
9245 }
9247 \f
9248 struct pair_fn_data
9249 {
9250 tree_fn_t fn;
9251 tree_fn_t any_fn;
9253 /* True when we should also visit template parameters that occur in
9254 non-deduced contexts. */
9257 };
9259 /* Called from for_each_template_parm via walk_tree. */
9261 static tree
9263 {
9270 #define WALK_SUBTREE(NODE) \
9271 do \
9272 { \
9273 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
9274 pfd->include_nondeduced_p, \
9275 pfd->any_fn); \
9276 if (result) goto out; \
9277 } \
9278 while (0)
9288 {
9292 /* Fall through. */
9298 else
9308 /* Since we're not going to walk subtrees, we have to do this
9309 explicitly here. */
9311 /* Fall through. */
9314 /* Check the return type. */
9317 /* Check the parameter types. Since default arguments are not
9318 instantiated until they are needed, the TYPE_ARG_TYPES may
9319 contain expressions that involve template parameters. But,
9320 no-one should be looking at them yet. And, once they're
9321 instantiated, they don't contain template parameters, so
9322 there's no point in looking at them then, either. */
9323 {
9324 tree parm;
9329 /* Since we've already handled the TYPE_ARG_TYPES, we don't
9330 want walk_tree walking into them itself. */
9332 }
9335 {
9339 }
9356 /* Fall through. */
9368 /* Record template parameters such as `T' inside `TT<T>'. */
9370 /* Fall through. */
9382 /* A template template parameter is encountered. */
9386 /* Already substituted template template parameter */
9391 /* A template-id in a TYPENAME_TYPE might be a deduced context after
9392 partial instantiation. */
9404 /* If there's no type, then this thing must be some expression
9405 involving template parameters. */
9427 }
9429 #undef WALK_SUBTREE
9431 /* We didn't find any template parameters we liked. */
9432 out:
9434 }
9436 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
9437 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
9438 call FN with the parameter and the DATA.
9439 If FN returns nonzero, the iteration is terminated, and
9440 for_each_template_parm returns 1. Otherwise, the iteration
9441 continues. If FN never returns a nonzero value, the value
9442 returned by for_each_template_parm is 0. If FN is NULL, it is
9443 considered to be the function which always returns 1.
9445 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
9446 parameters that occur in non-deduced contexts. When false, only
9447 visits those template parameters that can be deduced. */
9449 static tree
9453 tree_fn_t any_fn)
9454 {
9456 tree result;
9458 /* Set up. */
9464 /* Walk the tree. (Conceptually, we would like to walk without
9465 duplicates, but for_each_template_parm_r recursively calls
9466 for_each_template_parm, so we would need to reorganize a fair
9467 bit to use walk_tree_without_duplicates, so we keep our own
9468 visited list.) */
9471 else
9474 for_each_template_parm_r,
9478 /* Clean up. */
9480 {
9483 }
9486 }
9488 /* Returns true if T depends on any template parameter. */
9490 int
9492 {
9522 else
9523 {
9526 }
9531 }
9533 /* Returns true iff current_function_decl is an incompletely instantiated
9534 template. Useful instead of processing_template_decl because the latter
9535 is set to 0 during instantiate_non_dependent_expr. */
9537 bool
9539 {
9548 }
9550 /* Returns true if T depends on any template parameter with level LEVEL. */
9552 bool
9554 {
9557 }
9559 /* Returns true if the signature of DECL depends on any template parameter from
9560 its enclosing class. */
9562 bool
9564 {
9574 template_parm_outer_level,
9584 }
9586 /* Returns TRUE iff INST is an instantiation we don't need to do in an
9587 ill-formed translation unit, i.e. a variable or function that isn't
9588 usable in a constant expression. */
9592 {
9597 }
9599 /* Returns TRUE iff we should refuse to instantiate DECL because it's
9600 neglectable and instantiated from within an erroneous instantiation. */
9602 static bool
9604 {
9615 }
9623 /* We're starting to instantiate D; record the template instantiation context
9624 for diagnostics and to restore it later. */
9626 bool
9628 {
9630 }
9632 /* We're starting to instantiate D; record the template instantiation context
9633 at LOC for diagnostics and to restore it later. */
9635 bool
9637 {
9641 {
9642 /* Tell error.c not to try to instantiate any templates. */
9645 "template instantiation depth exceeds maximum of %d"
9647 max_tinst_depth);
9649 }
9651 /* If the current instantiation caused problems, don't let it instantiate
9652 anything else. Do allow deduction substitution and decls usable in
9653 constant expressions. */
9657 /* When not -quiet, dump template instantiations other than functions, since
9658 announce_function will take care of those. */
9677 }
9679 /* We're done instantiating this template; return to the instantiation
9680 context. */
9682 void
9684 {
9685 /* Restore the filename and line number stashed away when we started
9686 this instantiation. */
9690 }
9692 /* We're instantiating a deferred template; restore the template
9693 instantiation context in which the instantiation was requested, which
9694 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
9696 static tree
9698 {
9710 }
9712 /* Returns the TINST_LEVEL which gives the original instantiation
9713 context. */
9717 {
9723 }
9725 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
9726 vector of template arguments, as for tsubst.
9728 Returns an appropriate tsubst'd friend declaration. */
9730 static tree
9732 {
9733 tree new_friend;
9738 /* This was a friend declared with an explicit template
9739 argument list, e.g.:
9741 friend void f<>(T);
9743 to indicate that f was a template instantiation, not a new
9744 function declaration. Now, we have to figure out what
9745 instantiation of what template. */
9746 {
9748 tree new_args;
9749 tree tmpl;
9752 /* Friend functions are looked up in the containing namespace scope.
9753 We must enter that scope, to avoid finding member functions of the
9754 current class with same name. */
9769 tsk_none);
9771 }
9775 /* The NEW_FRIEND will look like an instantiation, to the
9776 compiler, but is not an instantiation from the point of view of
9777 the language. For example, we might have had:
9779 template <class T> struct S {
9780 template <class U> friend void f(T, U);
9781 };
9783 Then, in S<int>, template <class U> void f(int, U) is not an
9784 instantiation of anything. */
9790 {
9794 }
9796 /* The mangled name for the NEW_FRIEND is incorrect. The function
9797 is not a template instantiation and should not be mangled like
9798 one. Therefore, we forget the mangling here; we'll recompute it
9799 later if we need it. */
9801 {
9804 }
9807 {
9808 tree old_decl;
9809 tree new_friend_template_info;
9810 tree new_friend_result_template_info;
9811 tree ns;
9814 /* We must save some information from NEW_FRIEND before calling
9815 duplicate decls since that function will free NEW_FRIEND if
9816 possible. */
9818 new_friend_is_defn =
9823 {
9824 /* This declaration is a `primary' template. */
9827 new_friend_result_template_info
9829 }
9830 else
9833 /* Inside pushdecl_namespace_level, we will push into the
9834 current namespace. However, the friend function should go
9835 into the namespace of the template. */
9845 {
9846 /* This new friend declaration matched an existing
9847 declaration. For example, given:
9849 template <class T> void f(T);
9850 template <class U> class C {
9851 template <class T> friend void f(T) {}
9852 };
9854 the friend declaration actually provides the definition
9855 of `f', once C has been instantiated for some type. So,
9856 old_decl will be the out-of-class template declaration,
9857 while new_friend is the in-class definition.
9859 But, if `f' was called before this point, the
9860 instantiation of `f' will have DECL_TI_ARGS corresponding
9861 to `T' but not to `U', references to which might appear
9862 in the definition of `f'. Previously, the most general
9863 template for an instantiation of `f' was the out-of-class
9864 version; now it is the in-class version. Therefore, we
9865 run through all specialization of `f', adding to their
9866 DECL_TI_ARGS appropriately. In particular, they need a
9867 new set of outer arguments, corresponding to the
9868 arguments for this class instantiation.
9870 The same situation can arise with something like this:
9872 friend void f(int);
9873 template <class T> class C {
9874 friend void f(T) {}
9875 };
9877 when `C<int>' is instantiated. Now, `f(int)' is defined
9878 in the class. */
9881 /* On the other hand, if the in-class declaration does
9882 *not* provide a definition, then we don't want to alter
9883 existing definitions. We can just leave everything
9884 alone. */
9885 ;
9886 else
9887 {
9891 /* Overwrite whatever template info was there before, if
9892 any, with the new template information pertaining to
9893 the declaration. */
9897 {
9898 /* We should have called reregister_specialization in
9899 duplicate_decls. */
9904 /* Instantiate it if the global has already been used. */
9908 }
9909 else
9910 {
9911 tree t;
9913 /* Indicate that the old function template is a partial
9914 instantiation. */
9922 /* Reassign any specializations already in the hash table
9923 to the new more general template, and add the
9924 additional template args. */
9928 {
9930 spec_entry elt;
9942 register_specialization
9945 }
9947 }
9948 }
9950 /* The information from NEW_FRIEND has been merged into OLD_DECL
9951 by duplicate_decls. */
9953 }
9954 }
9955 else
9956 {
9960 /* In the code
9961 template <class T> class C {
9962 template <class U> friend void C1<U>::f (); // case 1
9963 friend void C2<T>::f (); // case 2
9964 };
9965 we only need to make sure CONTEXT is a complete type for
9966 case 2. To distinguish between the two cases, we note that
9967 CONTEXT of case 1 remains dependent type after tsubst while
9968 this isn't true for case 2. */
9978 {
9980 /* do_friend adds the TEMPLATE_DECL for any member friend
9981 template even if it isn't a member template, i.e.
9982 template <class T> friend A<T>::f();
9983 Look through it in that case. */
9987 /* Check to see that the declaration is really present, and,
9988 possibly obtain an improved declaration. */
9993 }
9994 }
9997 }
9999 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
10000 template arguments, as for tsubst.
10002 Returns an appropriate tsubst'd friend type or error_mark_node on
10003 failure. */
10005 static tree
10007 {
10008 tree tmpl;
10011 {
10014 }
10019 else
10027 {
10028 /* The friend template has already been declared. Just
10029 check to see that the declarations match, and install any new
10030 default parameters. We must tsubst the default parameters,
10031 of course. We only need the innermost template parameters
10032 because that is all that redeclare_class_template will look
10033 at. */
10036 {
10044 }
10045 }
10046 else
10047 {
10048 /* The friend template has not already been declared. In this
10049 case, the instantiation of the template class will cause the
10050 injection of this template into the namespace scope. */
10054 {
10055 /* The new TMPL is not an instantiation of anything, so we
10056 forget its origins. We don't reset CLASSTYPE_TI_TEMPLATE
10057 for the new type because that is supposed to be the
10058 corresponding template decl, i.e., TMPL. */
10065 /* It is hidden. */
10070 /* Inject this template into the enclosing namspace scope. */
10072 }
10073 }
10077 else
10081 }
10083 /* Returns zero if TYPE cannot be completed later due to circularity.
10084 Otherwise returns one. */
10086 static int
10088 {
10098 else
10100 }
10105 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
10106 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
10108 static tree
10111 {
10120 {
10127 clauses
10131 else
10133 }
10134 /* If the first attribute argument is an identifier, don't
10135 pass it through tsubst. Attributes like mode, format,
10136 cleanup and several target specific attributes expect it
10137 unmodified. */
10139 {
10140 tree chain
10145 }
10147 {
10148 /* An attribute pack expansion. */
10157 {
10161 }
10163 }
10164 else
10171 }
10173 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
10174 unchanged or a new TREE_LIST chain. */
10176 static tree
10179 {
10184 {
10188 }
10192 {
10195 {
10198 {
10200 do
10205 }
10206 }
10208 }
10211 }
10213 /* Apply any attributes which had to be deferred until instantiation
10214 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
10215 ARGS, COMPLAIN, IN_DECL are as tsubst. */
10217 static void
10220 {
10222 tree t;
10229 {
10233 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
10234 to our attributes parameter. */
10236 }
10237 else
10238 {
10240 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
10241 lookup_template_class_1, and should be preserved. */
10245 }
10249 {
10253 }
10257 {
10262 {
10265 {
10269 do
10272 }
10273 else
10275 }
10278 }
10279 }
10281 /* Perform (or defer) access check for typedefs that were referenced
10282 from within the template TMPL code.
10283 This is a subroutine of instantiate_decl and instantiate_class_template.
10284 TMPL is the template to consider and TARGS is the list of arguments of
10285 that template. */
10287 static void
10289 {
10290 location_t saved_location;
10301 {
10313 /* Make access check error messages point to the location
10314 of the use of the typedef. */
10318 tf_warning_or_error);
10319 }
10321 }
10323 static tree
10325 {
10327 tree typedecl;
10328 tree pbinfo;
10329 tree base_list;
10331 tree fn_context;
10340 /* Figure out which template is being instantiated. */
10344 /* Determine what specialization of the original template to
10345 instantiate. */
10348 {
10351 }
10353 {
10354 /* This TYPE is actually an instantiation of a partial
10355 specialization. We replace the innermost set of ARGS with
10356 the arguments appropriate for substitution. For example,
10357 given:
10359 template <class T> struct S {};
10360 template <class T> struct S<T*> {};
10362 and supposing that we are instantiating S<int*>, ARGS will
10363 presently be {int*} -- but we need {int}. */
10366 }
10367 else
10368 {
10371 }
10373 /* If the template we're instantiating is incomplete, then clearly
10374 there's nothing we can do. */
10378 /* If we've recursively instantiated too many templates, stop. */
10382 /* Now we're really doing the instantiation. Mark the type as in
10383 the process of being defined. */
10386 /* We may be in the middle of deferred access check. Disable
10387 it now. */
10394 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
10399 else
10400 {
10403 }
10404 /* Use #pragma pack from the template context. */
10410 /* Set the input location to the most specialized template definition.
10411 This is needed if tsubsting causes an error. */
10423 {
10426 /* Adjust visibility for template arguments. */
10428 }
10434 /* We should never instantiate a nested class before its enclosing
10435 class; we need to look up the nested class by name before we can
10436 instantiate it, and that lookup should instantiate the enclosing
10437 class. */
10443 {
10444 tree pbase_binfo;
10445 tree pushed_scope;
10448 /* We must enter the scope containing the type, as that is where
10449 the accessibility of types named in dependent bases are
10450 looked up from. */
10453 /* Substitute into each of the bases to determine the actual
10454 basetypes. */
10456 {
10457 tree base;
10463 {
10464 expanded_bases =
10471 }
10474 {
10476 /* Extract the already-expanded base class. */
10478 else
10479 /* Substitute to figure out the base class. */
10481 NULL_TREE);
10489 }
10490 }
10492 /* The list is now in reverse order; correct that. */
10497 }
10498 /* Now call xref_basetypes to set up all the base-class
10499 information. */
10507 /* Now that our base classes are set up, enter the scope of the
10508 class, so that name lookups into base classes, etc. will work
10509 correctly. This is precisely analogous to what we do in
10510 begin_class_definition when defining an ordinary non-template
10511 class, except we also need to push the enclosing classes. */
10514 /* Now members are processed in the order of declaration. */
10517 {
10521 {
10523 {
10524 /* Build new CLASSTYPE_NESTED_UTDS. */
10526 tree newtag;
10532 /* If the member is a class template, then -- even after
10533 substitution -- there may be dependent types in the
10534 template argument list for the class. We increment
10535 PROCESSING_TEMPLATE_DECL so that dependent_type_p, as
10536 that function will assume that no types are dependent
10537 when outside of a template. */
10547 {
10551 /* Unfortunately, lookup_template_class sets
10552 CLASSTYPE_IMPLICIT_INSTANTIATION for a partial
10553 instantiation (i.e., for the type of a member
10554 template class nested within a template class.)
10555 This behavior is required for
10556 maybe_process_partial_specialization to work
10557 correctly, but is not accurate in this case;
10558 the TAG is not an instantiation of anything.
10559 (The corresponding TEMPLATE_DECL is an
10560 instantiation, but the TYPE is not.) */
10563 /* Now, we call pushtag to put this NEWTAG into the scope of
10564 TYPE. We first set up the IDENTIFIER_TYPE_VALUE to avoid
10565 pushtag calling push_template_decl. We don't have to do
10566 this for enums because it will already have been done in
10567 tsubst_enum. */
10571 }
10572 }
10574 {
10575 tree r;
10584 /* Instantiate members marked with attribute used. */
10590 }
10593 /* A closure type for a lambda in a default argument for a
10594 member template. Ignore it; it will be instantiated with
10596 else
10597 {
10598 /* Build new TYPE_FIELDS. */
10600 {
10601 tree condition;
10604 condition =
10614 }
10616 {
10617 tree r;
10621 /* The file and line for this declaration, to
10622 assist in error message reporting. Since we
10623 called push_tinst_level above, we don't need to
10624 restore these. */
10634 {
10635 /* A capture pack became multiple fields. */
10638 }
10641 {
10645 {
10646 /* In [temp.inst]:
10648 [t]he initialization (and any associated
10649 side-effects) of a static data member does
10650 not occur unless the static data member is
10651 itself used in a way that requires the
10652 definition of the static data member to
10653 exist.
10655 Therefore, we do not substitute into the
10656 initialized for the static data member here. */
10657 finish_static_data_member_decl
10663 /* Instantiate members marked with attribute used. */
10666 }
10668 {
10669 /* Determine whether R has a valid type and can be
10670 completed later. If R is invalid, then its type
10671 is replaced by error_mark_node. */
10677 {
10678 /* If R's type couldn't be completed and
10679 it isn't a flexible array member (whose
10680 type is incomplete by definition) give
10681 an error. */
10684 }
10685 }
10687 /* If it is a TYPE_DECL for a class-scoped ENUMERAL_TYPE,
10688 such a thing will already have been added to the field
10689 list by tsubst_enum in finish_member_declaration in the
10690 CLASSTYPE_NESTED_UTDS case above. */
10694 {
10697 }
10698 }
10699 }
10700 }
10701 }
10702 else
10703 {
10706 {
10707 /* Build new CLASSTYPE_FRIEND_CLASSES. */
10713 {
10714 /* template <class T> friend class C; */
10717 }
10719 {
10720 /* template <class T> friend class C::D; */
10726 }
10729 {
10730 /* This could be either
10732 friend class T::C;
10734 when dependent_type_p is false or
10736 template <class U> friend class T::C;
10738 otherwise. */
10739 /* Bump processing_template_decl in case this is something like
10740 template <class T> friend struct A<T>::B. */
10747 }
10751 {
10752 /* friend class C;
10754 where C hasn't been declared yet. Let's lookup name
10755 from namespace scope directly, bypassing any name that
10756 come from dependent base class. */
10759 /* The call to xref_tag_from_type does injection for friend
10760 classes. */
10762 friend_type =
10766 }
10768 /* friend class C<T>; */
10771 /* Otherwise it's
10773 friend class C;
10775 where C is already declared or
10777 friend class C<int>;
10779 We don't have to do anything in these cases. */
10782 /* Trick make_friend_class into realizing that the friend
10783 we're adding is a template, not an ordinary class. It's
10784 important that we use make_friend_class since it will
10785 perform some error-checking and output cross-reference
10786 information. */
10794 }
10795 else
10796 {
10797 /* Build new DECL_FRIENDLIST. */
10798 tree r;
10800 /* The file and line for this declaration, to
10801 assist in error message reporting. Since we
10802 called push_tinst_level above, we don't need to
10803 restore these. */
10807 {
10810 }
10815 {
10818 }
10819 }
10820 }
10821 }
10824 {
10825 /* Restore these before substituting into the lambda capture
10826 initializers. */
10829 }
10832 {
10835 {
10841 {
10842 /* Set function_depth to avoid garbage collection. */
10846 }
10848 /* We need to instantiate the capture list from the template
10849 after we've instantiated the closure members, but before we
10850 consider adding the conversion op. Also keep any captures
10851 that may have been added during instantiation of the op(). */
10853 tree tmpl_cap
10862 }
10863 else
10865 }
10867 /* Set the file and line number information to whatever is given for
10868 the class itself. This puts error messages involving generated
10869 implicit functions at a predictable point, and the same point
10870 that would be used for non-template classes. */
10877 /* We don't instantiate default arguments for member functions. 14.7.1:
10879 The implicit instantiation of a class template specialization causes
10880 the implicit instantiation of the declarations, but not of the
10881 definitions or default arguments, of the class member functions,
10882 member classes, static data members and member templates.... */
10884 /* Some typedefs referenced from within the template code need to be access
10885 checked at template instantiation time, i.e now. These types were
10886 added to the template at parsing time. Let's get those and perform
10887 the access checks then. */
10897 /* The vtable for a template class can be emitted in any translation
10898 unit in which the class is instantiated. When there is no key
10899 method, however, finish_struct_1 will already have added TYPE to
10900 the keyed_classes. */
10905 }
10907 /* Wrapper for instantiate_class_template_1. */
10909 tree
10911 {
10912 tree ret;
10917 }
10919 static tree
10921 {
10922 tree r;
10928 else
10929 {
10936 }
10938 }
10940 /* Given a function parameter pack TMPL_PARM and some function parameters
10941 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
10942 and set *SPEC_P to point at the next point in the list. */
10944 tree
10946 {
10947 /* Collect all of the extra "packed" parameters into an
10948 argument pack. */
10949 tree parmvec;
10959 /* Fill in PARMVEC and PARMTYPEVEC with all of the parameters. */
10965 /* Build the argument packs. */
10970 }
10972 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
10973 NONTYPE_ARGUMENT_PACK. */
10975 static tree
10977 {
10979 }
10981 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
10982 pack expansion with no extra args, 2 if it has extra args, or 0
10983 if it is not a pack expansion. */
10985 static int
10987 {
10993 /* A decl pack is itself an expansion. */
11000 }
11003 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
11005 static tree
11007 {
11014 }
11016 /* This is a subroutine of tsubst_pack_expansion.
11018 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
11019 mechanism to store the (non complete list of) arguments of the
11020 substitution and return a non substituted pack expansion, in order
11021 to wait for when we have enough arguments to really perform the
11022 substitution. */
11024 static bool
11028 {
11029 /* If one pack has an expansion and another pack has a normal
11030 argument or if one pack has an empty argument and an another
11031 one hasn't then tsubst_pack_expansion cannot perform the
11032 substitution and need to fall back on the
11033 PACK_EXPANSION_EXTRA mechanism. */
11041 {
11044 parm_pack;
11046 {
11051 /* We can't substitute a pack expansion with extra args into
11052 our pattern. */
11056 else
11058 }
11062 }
11064 }
11066 /* [temp.variadic]/6 says that:
11068 The instantiation of a pack expansion [...]
11069 produces a list E1,E2, ..., En, where N is the number of elements
11070 in the pack expansion parameters.
11072 This subroutine of tsubst_pack_expansion produces one of these Ei.
11074 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
11075 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
11076 PATTERN, and each TREE_VALUE is its corresponding argument pack.
11077 INDEX is the index 'i' of the element Ei to produce. ARGS,
11078 COMPLAIN, and IN_DECL are the same parameters as for the
11079 tsubst_pack_expansion function.
11081 The function returns the resulting Ei upon successful completion,
11082 or error_mark_node.
11084 Note that this function possibly modifies the ARGS parameter, so
11085 it's the responsibility of the caller to restore it. */
11087 static tree
11089 tree parm_packs,
11091 tree args /* This parm gets
11093 tsubst_flags_t complain,
11094 tree in_decl)
11095 {
11096 tree t;
11099 /* For each parameter pack, change the substitution of the parameter
11100 pack to the ith argument in its argument pack, then expand the
11101 pattern. */
11103 {
11108 ith_elem_is_expansion |=
11111 /* Select the Ith argument from the pack. */
11114 {
11116 {
11121 }
11122 else
11124 }
11125 else
11126 {
11131 {
11133 /* Update the corresponding argument. */
11135 }
11136 else
11137 /* Re-use the ARGUMENT_PACK_SELECT. */
11139 }
11141 }
11143 /* Substitute into the PATTERN with the (possibly altered)
11144 arguments. */
11146 /* Expanding a fixed parameter pack from
11147 coerce_template_parameter_pack. */
11152 {
11155 else
11158 }
11162 else
11165 /* If the Ith argument pack element is a pack expansion, then
11166 the Ith element resulting from the substituting is going to
11167 be a pack expansion as well. */
11172 }
11174 /* When the unexpanded parameter pack in a fold expression expands to an empty
11175 sequence, the value of the expression is as follows; the program is
11176 ill-formed if the operator is not listed in this table.
11178 && true
11179 || false
11180 , void() */
11182 tree
11184 {
11188 {
11197 }
11203 }
11205 /* Given a fold-expression T and a current LEFT and RIGHT operand,
11206 form an expression that combines the two terms using the
11207 operator of T. */
11209 static tree
11211 {
11215 // Handle compound assignment operators.
11220 {
11230 complain);
11231 }
11232 }
11234 /* Substitute ARGS into the pack of a fold expression T. */
11238 {
11240 }
11242 /* Substitute ARGS into the pack of a fold expression T. */
11246 {
11248 }
11250 /* Expand a PACK of arguments into a grouped as left fold.
11251 Given a pack containing elements A0, A1, ..., An and an
11252 operator @, this builds the expression:
11254 ((A0 @ A1) @ A2) ... @ An
11256 Note that PACK must not be empty.
11258 The operator is defined by the original fold expression T. */
11260 static tree
11262 {
11265 {
11268 }
11270 }
11272 /* Substitute into a unary left fold expression. */
11274 static tree
11276 tree in_decl)
11277 {
11282 {
11286 }
11289 else
11291 }
11293 /* Substitute into a binary left fold expression.
11295 Do ths by building a single (non-empty) vector of argumnts and
11296 building the expression from those elements. */
11298 static tree
11300 tree in_decl)
11301 {
11310 {
11315 }
11323 }
11325 /* Expand a PACK of arguments into a grouped as right fold.
11326 Given a pack containing elementns A0, A1, ..., and an
11327 operator @, this builds the expression:
11329 A0@ ... (An-2 @ (An-1 @ An))
11331 Note that PACK must not be empty.
11333 The operator is defined by the original fold expression T. */
11335 tree
11337 {
11338 // Build the expression.
11342 {
11345 }
11347 }
11349 /* Substitute into a unary right fold expression. */
11351 static tree
11353 tree in_decl)
11354 {
11359 {
11363 }
11366 else
11368 }
11370 /* Substitute into a binary right fold expression.
11372 Do ths by building a single (non-empty) vector of arguments and
11373 building the expression from those elements. */
11375 static tree
11377 tree in_decl)
11378 {
11387 {
11392 }
11401 }
11404 /* Substitute ARGS into T, which is an pack expansion
11405 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
11406 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
11407 (if only a partial substitution could be performed) or
11408 ERROR_MARK_NODE if there was an error. */
11409 tree
11411 tree in_decl)
11412 {
11413 tree pattern;
11417 tree result;
11425 /* Add in any args remembered from an earlier partial instantiation. */
11430 /* Determine the argument packs that will instantiate the parameter
11431 packs used in the expansion expression. While we're at it,
11432 compute the number of arguments to be expanded and make sure it
11433 is consistent. */
11436 {
11443 {
11448 else
11451 }
11453 {
11454 /* ??? Support use in other patterns. */
11458 }
11460 {
11461 /* We know we have correct local_specializations if this
11462 expansion is at function scope, or if we're dealing with a
11463 local parameter in a requires expression; for the latter,
11464 tsubst_requires_expr set it up appropriately. */
11467 else
11468 /* We can't rely on local_specializations for a parameter
11469 name used later in a function declaration (such as in a
11470 late-specified return type). Even if it exists, it might
11471 have the wrong value for a recursive call. */
11475 {
11476 /* This parameter pack was used in an unevaluated context. Just
11477 make a dummy decl, since it's only used for its type. */
11480 /* Partial instantiation of the parm_pack, we can't build
11481 up an argument pack yet. */
11483 else
11485 }
11486 }
11489 else
11490 {
11496 }
11503 /* This can only happen if we forget to expand an argument
11504 pack somewhere else. Just return an error, silently. */
11505 {
11509 }
11512 {
11516 /* Don't bother trying to do a partial substitution with
11517 incomplete packs; we'll try again after deduction. */
11524 {
11529 pattern);
11530 else
11532 pattern);
11534 }
11536 /* Keep track of the parameter packs and their corresponding
11537 argument packs. */
11540 }
11541 else
11542 {
11543 /* We can't substitute for this parameter pack. We use a flag as
11544 well as the missing_level counter because function parameter
11545 packs don't have a level. */
11548 }
11549 }
11551 /* If the expansion is just T..., return the matching argument pack, unless
11552 we need to call convert_from_reference on all the elements. This is an
11553 important optimization; see c++/68422. */
11556 {
11558 /* Types need no adjustment, nor does sizeof..., and if we still have
11559 some pack expansion args we won't do anything yet. */
11564 /* Also optimize expression pack expansions if we can tell that the
11565 elements won't have reference type. */
11571 /* Otherwise use the normal path so we get convert_from_reference. */
11572 }
11574 /* We cannot expand this expansion expression, because we don't have
11575 all of the argument packs we need. */
11577 {
11578 /* We got some full packs, but we can't substitute them in until we
11579 have values for all the packs. So remember these until then. */
11584 }
11586 {
11587 /* There were no real arguments, we're just replacing a parameter
11588 pack with another version of itself. Substitute into the
11589 pattern and return a PACK_EXPANSION_*. The caller will need to
11590 deal with that. */
11594 else
11598 }
11603 {
11604 /* We're in a late-specified return type, so create our own local
11605 specializations map; the current map is either NULL or (in the
11606 case of recursive unification) might have bindings that we don't
11607 want to use or alter. */
11610 }
11612 /* For each argument in each argument pack, substitute into the
11613 pattern. */
11617 {
11619 i,
11621 in_decl);
11624 {
11627 }
11628 }
11630 /* Update ARGS to restore the substitution from parameter packs to
11631 their argument packs. */
11633 {
11639 else
11640 {
11648 /* Update the corresponding argument. */
11652 else
11654 }
11655 }
11658 {
11661 }
11663 /* If the dependent pack arguments were such that we end up with only a
11664 single pack expansion again, there's no need to keep it in a TREE_VEC. */
11670 }
11672 /* Given PARM_DECL PARM, find the corresponding PARM_DECL in the template
11673 TMPL. We do this using DECL_PARM_INDEX, which should work even with
11674 parameter packs; all parms generated from a function parameter pack will
11675 have the same DECL_PARM_INDEX. */
11677 tree
11679 {
11681 tree patparm;
11684 {
11690 }
11691 else
11692 {
11697 }
11700 }
11702 /* Make an argument pack out of the TREE_VEC VEC. */
11704 static tree
11706 {
11707 tree pack;
11711 else
11712 {
11715 }
11718 }
11720 /* Return an exact copy of template args T that can be modified
11721 independently. */
11723 static tree
11725 {
11733 {
11738 }
11744 }
11746 /* Substitute ARGS into the vector or list of template arguments T. */
11748 static tree
11750 {
11762 {
11764 tree new_arg;
11769 {
11770 /* Substitute into an expansion expression. */
11774 /* Add to the expanded length adjustment the number of
11775 expanded arguments. We subtract one from this
11776 measurement, because the argument pack expression
11777 itself is already counted as 1 in
11778 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
11779 the argument pack is empty. */
11781 }
11783 {
11784 /* Substitute into each of the arguments. */
11793 else
11798 }
11799 else
11808 }
11813 /* Make space for the expanded arguments coming from template
11814 argument packs. */
11816 /* ORIG_T can contain TREE_VECs. That happens if ORIG_T contains the
11817 arguments for a member template.
11818 In that case each TREE_VEC in ORIG_T represents a level of template
11819 arguments, and ORIG_T won't carry any non defaulted argument count.
11820 It will rather be the nested TREE_VECs that will carry one.
11821 In other words, ORIG_T carries a non defaulted argument count only
11822 if it doesn't contain any nested TREE_VEC. */
11824 {
11828 }
11830 {
11834 {
11837 /* Now expand the template argument pack "in place". */
11840 }
11841 else
11842 {
11844 out++;
11845 }
11846 }
11849 }
11851 /* Substitute ARGS into one level PARMS of template parameters. */
11853 static tree
11855 {
11862 {
11870 }
11873 }
11875 /* Return the result of substituting ARGS into the template parameters
11876 given by PARMS. If there are m levels of ARGS and m + n levels of
11877 PARMS, then the result will contain n levels of PARMS. For
11878 example, if PARMS is `template <class T> template <class U>
11879 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
11880 result will be `template <int*, double, class V>'. */
11882 static tree
11884 {
11888 /* When substituting into a template, we must set
11889 PROCESSING_TEMPLATE_DECL as the template parameters may be
11890 dependent if they are based on one-another, and the dependency
11891 predicates are short-circuit outside of templates. */
11898 {
11905 }
11910 }
11912 /* Return the result of substituting ARGS into one template parameter
11913 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
11914 parameter and which TREE_PURPOSE is the default argument of the
11915 template parameter. */
11917 static tree
11919 {
11940 }
11942 /* Substitute the ARGS into the indicated aggregate (or enumeration)
11943 type T. If T is not an aggregate or enumeration type, it is
11944 handled as if by tsubst. IN_DECL is as for tsubst. If
11945 ENTERING_SCOPE is nonzero, T is the context for a template which
11946 we are presently tsubst'ing. Return the substituted value. */
11948 static tree
11950 tree args,
11951 tsubst_flags_t complain,
11952 tree in_decl,
11954 {
11959 {
11964 /* Fall through. */
11968 {
11969 tree argvec;
11970 tree context;
11971 tree r;
11975 /* In "sizeof(X<I>)" we need to evaluate "I". */
11981 /* First, determine the context for the type we are looking
11982 up. */
11985 {
11988 /* If context is a nested class inside a class template,
11989 it may still need to be instantiated (c++/33959). */
11991 }
11993 /* Then, figure out what arguments are appropriate for the
11994 type we are trying to find. For example, given:
11996 template <class T> struct S;
11997 template <class T, class U> void f(T, U) { S<U> su; }
11999 and supposing that we are instantiating f<int, double>,
12000 then our ARGS will be {int, double}, but, when looking up
12001 S we only want {double}. */
12006 else
12007 {
12011 }
12017 }
12018 else
12019 /* This is not a template type, so there's nothing to do. */
12024 }
12025 }
12029 /* Substitute into the default argument ARG (a default argument for
12030 FN), which has the indicated TYPE. */
12032 tree
12034 tsubst_flags_t complain)
12035 {
12040 /* This can happen in invalid code. */
12055 /* This default argument came from a template. Instantiate the
12056 default argument here, not in tsubst. In the case of
12057 something like:
12059 template <class T>
12060 struct S {
12061 static T t();
12062 void f(T = t());
12063 };
12065 we must be careful to do name lookup in the scope of S<T>,
12066 rather than in the current class. */
12068 /* The "this" pointer is not valid in a default argument. */
12070 {
12075 }
12080 /* The default argument expression may cause implicitly defined
12081 member functions to be synthesized, which will result in garbage
12082 collection. We must treat this situation as if we were within
12083 the body of function so as to avoid collecting live data on the
12084 stack. */
12094 /* Restore the "this" pointer. */
12096 {
12099 }
12106 /* Make sure the default argument is reasonable. */
12112 {
12116 }
12119 }
12121 /* Substitute into all the default arguments for FN. */
12123 static void
12125 {
12126 tree arg;
12127 tree tmpl_args;
12131 /* If this function is not yet instantiated, we certainly don't need
12132 its default arguments. */
12135 /* Don't do this again for clones. */
12141 arg;
12147 complain);
12148 }
12150 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
12152 static tree
12154 tree lambda_fntype)
12155 {
12160 /* Nobody should be tsubst'ing into non-template functions. */
12164 {
12165 /* If T is not dependent, just return it. */
12169 /* Calculate the most general template of which R is a
12170 specialization, and the complete set of arguments used to
12171 specialize R. */
12174 (DECL_TEMPLATE_RESULT
12180 /* Check to see if we already have this specialization. */
12182 {
12186 }
12188 /* We can see more levels of arguments than parameters if
12189 there was a specialization of a member template, like
12190 this:
12192 template <class T> struct S { template <class U> void f(); }
12193 template <> template <class U> void S<int>::f(U);
12195 Here, we'll be substituting into the specialization,
12196 because that's where we can find the code we actually
12197 want to generate, but we'll have enough arguments for
12198 the most general template.
12200 We also deal with the peculiar case:
12202 template <class T> struct S {
12203 template <class U> friend void f();
12204 };
12205 template <class U> void f() {}
12206 template S<int>;
12207 template void f<double>();
12209 Here, the ARGS for the instantiation of will be {int,
12210 double}. But, we only need as many ARGS as there are
12211 levels of template parameters in CODE_PATTERN. We are
12212 careful not to get fooled into reducing the ARGS in
12213 situations like:
12215 template <class T> struct S { template <class U> void f(U); }
12216 template <class T> template <> void S<T>::f(int) {}
12218 which we can spot because the pattern will be a
12219 specialization in this case. */
12226 }
12227 else
12228 {
12229 /* This special case arises when we have something like this:
12231 template <class T> struct S {
12232 friend void f<int>(int, double);
12233 };
12235 Here, the DECL_TI_TEMPLATE for the friend declaration
12236 will be an IDENTIFIER_NODE. We are being called from
12237 tsubst_friend_function, and we want only to create a
12238 new decl (R) with appropriate types so that we can call
12239 determine_specialization. */
12242 }
12259 /* If we hit excessive deduction depth, the type is bogus even if
12260 it isn't error_mark_node, so don't build a decl. */
12264 /* We do NOT check for matching decls pushed separately at this
12265 point, as they may not represent instantiations of this
12266 template, and in any case are considered separate under the
12267 discrete model. */
12271 /* Clear out the mangled name and RTL for the instantiation. */
12274 /* Leave DECL_INITIAL set on deleted instantiations. */
12279 /* OpenMP UDRs have the only argument a reference to the declared
12280 type. We want to diagnose if the declared type is a reference,
12281 which is invalid, but as references to references are usually
12282 quietly merged, diagnose it here. */
12284 {
12285 tree argtype
12290 "reference type %qT in "
12294 argtype);
12295 }
12298 /* Type-conversion operator. Reconstruct the name, in
12299 case it's the name of one of the template's parameters. */
12309 {
12313 }
12320 /* If this is an instantiation of a function with internal
12321 linkage, we already know what object file linkage will be
12322 assigned to the instantiation. */
12331 /* We'll re-clone as appropriate in instantiate_template. */
12334 /* If we aren't complaining now, return on error before we register
12335 the specialization so that we'll complain eventually. */
12341 /* When instantiating a constrained member, substitute
12342 into the constraints to create a new constraint. */
12345 {
12348 }
12350 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
12351 this in the special friend case mentioned above where
12352 GEN_TMPL is NULL. */
12354 {
12359 tree new_r
12362 /* We instantiated this while substituting into
12363 the type earlier (template/friend54.C). */
12366 /* We're not supposed to instantiate default arguments
12367 until they are called, for a template. But, for a
12368 declaration like:
12370 template <class T> void f ()
12371 { extern void g(int i = T()); }
12373 we should do the substitution when the template is
12374 instantiated. We handle the member function case in
12375 instantiate_class_template since the default arguments
12376 might refer to other members of the class. */
12381 }
12382 else
12385 /* Copy the list of befriending classes. */
12389 {
12393 }
12396 {
12400 /* If this is an instantiation of a member template, clone it.
12401 If it isn't, that'll be handled by
12402 clone_constructors_and_destructors. */
12405 }
12416 /* Possibly limit visibility based on template args. */
12419 {
12423 }
12432 }
12434 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
12436 static tree
12438 tree lambda_fntype)
12439 {
12440 /* We can get here when processing a member function template,
12441 member class template, or template template parameter. */
12444 tree spec;
12445 tree tmpl_args;
12446 tree full_args;
12447 tree r;
12451 {
12452 /* Template template parameter is treated here. */
12456 /* If we get a real template back, return it. This can happen in
12457 the context of most_specialized_partial_spec. */
12460 else
12461 /* The new TEMPLATE_DECL was built in
12462 reduce_template_parm_level. */
12465 }
12468 {
12469 /* We might already have an instance of this template.
12470 The ARGS are for the surrounding class type, so the
12471 full args contain the tsubst'd args for the context,
12472 plus the innermost args from the template decl. */
12476 /* Because this is a template, the arguments will still be
12477 dependent, even after substitution. If
12478 PROCESSING_TEMPLATE_DECL is not set, the dependency
12479 predicates will short-circuit. */
12487 /* If this is a default template template argument,
12488 tsubst might not have changed anything. */
12496 }
12498 /* Make a new template decl. It will be similar to the
12499 original, but will record the current template arguments.
12500 We also create a new function declaration, which is just
12501 like the old one, but points to this new template, rather
12502 than the old one. */
12507 // Build new template info linking to the original template decl.
12509 {
12512 }
12513 else
12516 /* The template parameters for this new template are all the
12517 template parameters for the old template, except the
12518 outermost level of parameters. */
12521 complain);
12525 {
12526 tree new_type;
12534 /* For a partial specialization, we need to keep pointing to
12535 the primary template. */
12541 }
12542 else
12543 {
12544 tree new_decl;
12548 else
12558 {
12561 }
12562 else
12563 {
12566 }
12567 }
12577 /* Record this non-type partial instantiation. */
12583 }
12585 /* True if FN is the op() for a lambda in an uninstantiated template. */
12587 bool
12589 {
12594 }
12596 /* True if FN is the op() for a lambda regenerated from a lambda in an
12597 uninstantiated template. */
12599 bool
12601 {
12604 }
12606 /* We're instantiating a variable from template function TCTX. Return the
12607 corresponding current enclosing scope. This gets complicated because lambda
12608 functions in templates are regenerated rather than instantiated, but generic
12609 lambda functions are subsequently instantiated. */
12611 static tree
12613 {
12621 {
12632 {
12636 }
12638 }
12640 }
12642 /* Substitute the ARGS into the T, which is a _DECL. Return the
12643 result of the substitution. Issue error and warning messages under
12644 control of COMPLAIN. */
12646 static tree
12648 {
12649 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
12650 location_t saved_loc;
12655 /* Set the filename and linenumber to improve error-reporting. */
12660 {
12670 {
12678 {
12679 /* If there is a local specialization that isn't a
12680 parameter pack, it means that we're doing a "simple"
12681 substitution from inside tsubst_pack_expansion. Just
12682 return the local specialization (which will be a single
12683 parm). */
12690 /* Expand the TYPE_PACK_EXPANSION that provides the types for
12691 the parameters in this function parameter pack. */
12695 {
12698 /* Zero-length parameter packs are boring. Just substitute
12699 into the chain. */
12703 }
12704 else
12705 {
12706 /* All we did was update the type. Make a note of that. */
12709 }
12710 }
12712 /* Loop through all of the parameters we'll build. When T is
12713 a function parameter pack, LEN is the number of expanded
12714 types in EXPANDED_TYPES; otherwise, LEN is 1. */
12717 {
12724 /* We're on the Ith parameter of the function parameter
12725 pack. */
12726 {
12727 /* Get the Ith type. */
12730 /* Rename the parameter to include the index. */
12733 }
12735 /* We're dealing with a normal parameter. */
12743 {
12746 else
12749 }
12759 /* Keep track of the first new parameter we
12760 generate. That's what will be returned to the
12761 caller. */
12765 /* Build a proper chain of parameters when substituting
12766 into a function parameter pack. */
12769 }
12771 /* If cp_unevaluated_operand is set, we're just looking for a
12772 single dummy parameter, so don't keep going. */
12777 /* FIRST_R contains the start of the chain we've built. */
12779 }
12783 {
12790 {
12791 /* This field is a lambda capture pack. Return a TREE_VEC of
12792 the expanded fields to instantiate_class_template_1 and
12793 store them in the specializations hash table as a
12794 NONTYPE_ARGUMENT_PACK so that tsubst_copy can find them. */
12798 {
12801 }
12802 else
12803 {
12804 /* All we did was update the type. Make a note of that. */
12807 }
12808 }
12811 {
12814 {
12818 }
12828 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
12829 number of bits. */
12835 {
12836 /* Set up DECL_TEMPLATE_INFO so that we can get at the
12837 NSDMI in perform_member_init. Still set DECL_INITIAL
12838 so that we know there is one. */
12843 }
12844 /* We don't have to set DECL_CONTEXT here; it is set by
12845 finish_member_declaration. */
12853 }
12856 {
12861 }
12862 }
12866 /* We reach here only for member using decls. We also need to check
12867 uses_template_parms because DECL_DEPENDENT_P is not set for a
12868 using-declaration that designates a member of the current
12869 instantiation (c++/53549). */
12872 {
12876 {
12881 {
12885 {
12888 }
12889 else
12890 {
12893 }
12895 }
12896 }
12897 else
12898 {
12904 else
12905 {
12908 }
12909 }
12910 }
12911 else
12912 {
12915 }
12920 {
12923 tree spec;
12925 tree ctx;
12934 {
12935 /* If this is the canonical decl, we don't have to
12936 mess with instantiations, and often we can't (for
12937 typename, template type parms and such). Note that
12938 TYPE_NAME is not correct for the above test if
12939 we've copied the type for a typedef. */
12945 }
12947 /* Check to see if we already have the specialization we
12948 need. */
12951 {
12952 /* T is a static data member or namespace-scope entity.
12953 We have to substitute into namespace-scope variables
12954 (not just variable templates) because of cases like:
12956 template <class T> void f() { extern T t; }
12958 where the entity referenced is not known until
12959 instantiation time. */
12963 {
12965 complain,
12967 /* If CTX is unchanged, then T is in fact the
12968 specialization we want. That situation occurs when
12969 referencing a static data member within in its own
12970 class. We can use pointer equality, rather than
12971 same_type_p, because DECL_CONTEXT is always
12972 canonical... */
12974 /* ... unless T is a member template; in which
12975 case our caller can be willing to create a
12976 specialization of that template represented
12977 by T. */
12981 }
12984 {
12989 argvec = (coerce_innermost_template_parms
12997 }
12998 }
12999 else
13000 {
13001 /* A local variable. */
13003 /* Subsequent calls to pushdecl will fill this in. */
13005 /* Unless this is a reference to a static variable from an
13006 enclosing function, in which case we need to fill it in now. */
13008 {
13012 }
13014 }
13015 /* If we already have the specialization we need, there is
13016 nothing more to do. */
13018 {
13021 }
13023 /* Create a new node for the specialization we need. */
13026 {
13029 else
13037 {
13038 /* Mask off any template args past the variable's context so we
13039 don't replace the auto with an unrelated argument. */
13043 /* This should never happen with the new lambda instantiation
13044 model, but keep the handling just in case. */
13047 }
13049 }
13051 {
13052 /* Even if the original location is out of scope, the
13053 newly substituted one is not. */
13060 {
13061 /* It may seem that this case cannot occur, since:
13063 typedef void f();
13064 void g() { f x; }
13066 declares a function, not a variable. However:
13068 typedef void f();
13069 template <typename T> void g() { T t; }
13070 template void g<f>();
13072 is an attempt to declare a variable with function
13073 type. */
13075 /* R is not yet sufficiently initialized, so we
13076 just use its name. */
13079 }
13081 /* Wait until cp_finish_decl to set this again, to handle
13082 circular dependency (template/instantiate6.C). */
13087 {
13092 {
13095 }
13097 }
13101 }
13107 /* Clear out the mangled name and RTL for the instantiation. */
13111 /* The initializer must not be expanded until it is required;
13112 see [temp.inst]. */
13116 {
13122 /* Possibly limit visibility based on template args. */
13125 {
13129 }
13131 }
13134 {
13135 /* A static data member declaration is always marked
13136 external when it is declared in-class, even if an
13137 initializer is present. We mimic the non-template
13138 processing here. */
13146 }
13147 else
13148 {
13153 }
13161 /* Preserve a typedef that names a type. */
13163 {
13167 /* An alias template specialization can be dependent
13168 even if its underlying type is not. */
13170 }
13173 }
13178 }
13179 #undef RETURN
13181 out:
13182 /* Restore the file and line information. */
13186 }
13188 /* Substitute into the ARG_TYPES of a function type.
13189 If END is a TREE_CHAIN, leave it and any following types
13190 un-substituted. */
13192 static tree
13194 tree args,
13195 tree end,
13196 tsubst_flags_t complain,
13197 tree in_decl)
13198 {
13199 tree remaining_arg_types;
13203 tree default_arg;
13214 {
13215 /* For a pack expansion, perform substitution on the
13216 entire expression. Later on, we'll handle the arguments
13217 one-by-one. */
13222 /* So that we'll spin through the parameters, one by one. */
13224 else
13225 {
13226 /* We only partially substituted into the parameter
13227 pack. Our type is TYPE_PACK_EXPANSION. */
13230 }
13231 }
13244 {
13246 {
13250 }
13252 }
13253 /* DR 657. */
13257 /* Do array-to-pointer, function-to-pointer conversion, and ignore
13258 top-level qualifiers as required. */
13261 /* We do not substitute into default arguments here. The standard
13262 mandates that they be instantiated only when needed, which is
13263 done in build_over_call. */
13266 /* Except that we do substitute default arguments under tsubst_lambda_expr,
13267 since the new op() won't have any associated template arguments for us
13268 to refer to later. */
13274 {
13275 /* We've instantiated a template before its default arguments
13276 have been parsed. This can happen for a nested template
13277 class, and is not an error unless we require the default
13278 argument in a call of this function. */
13279 remaining_arg_types =
13282 }
13283 else
13284 remaining_arg_types =
13286 }
13289 }
13291 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
13292 *not* handle the exception-specification for FNTYPE, because the
13293 initial substitution of explicitly provided template parameters
13294 during argument deduction forbids substitution into the
13295 exception-specification:
13297 [temp.deduct]
13299 All references in the function type of the function template to the
13300 corresponding template parameters are replaced by the specified tem-
13301 plate argument values. If a substitution in a template parameter or
13302 in the function type of the function template results in an invalid
13303 type, type deduction fails. [Note: The equivalent substitution in
13304 exception specifications is done only when the function is instanti-
13305 ated, at which point a program is ill-formed if the substitution
13306 results in an invalid type.] */
13308 static tree
13310 tree args,
13311 tsubst_flags_t complain,
13312 tree in_decl)
13313 {
13314 tree return_type;
13316 tree fntype;
13318 /* The TYPE_CONTEXT is not used for function/method types. */
13321 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
13322 failure. */
13326 {
13327 /* Substitute the argument types. */
13339 {
13340 /* DR 1207: 'this' is in scope in the trailing return type. */
13342 }
13344 /* Substitute the return type. */
13348 {
13351 }
13352 }
13353 else
13354 /* Substitute the return type. */
13359 /* DR 486 clarifies that creation of a function type with an
13360 invalid return type is a deduction failure. */
13363 {
13365 {
13368 else
13370 }
13372 }
13373 /* And DR 657. */
13378 {
13379 /* Substitute the argument types. */
13384 }
13386 /* Construct a new type node and return it. */
13388 {
13393 }
13394 else
13395 {
13397 /* Don't pick up extra function qualifiers from the basetype. */
13400 {
13401 /* [temp.deduct]
13403 Type deduction may fail for any of the following
13404 reasons:
13406 -- Attempting to create "pointer to member of T" when T
13407 is not a class type. */
13410 r);
13412 }
13417 }
13424 }
13426 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
13427 ARGS into that specification, and return the substituted
13428 specification. If there is no specification, return NULL_TREE. */
13430 static tree
13432 tree args,
13433 tsubst_flags_t complain,
13434 tree in_decl,
13436 {
13437 tree specs;
13438 tree new_specs;
13443 {
13444 /* A noexcept-specifier. */
13449 {
13450 /* Defer instantiation of noexcept-specifiers to avoid
13451 excessive instantiations (c++/49107). */
13454 {
13455 /* We already partially instantiated this member template,
13456 so combine the new args with the old. */
13461 }
13462 else
13463 {
13466 }
13467 }
13468 else
13469 new_specs = tsubst_copy_and_build
13473 }
13475 {
13478 else
13480 {
13481 tree spec;
13486 {
13487 /* Expand the pack expansion type. */
13490 in_decl);
13496 else
13497 {
13498 /* We're substituting into a member template, so
13499 we got a TYPE_PACK_EXPANSION back. Add that
13500 expansion and move on. */
13504 expanded_specs,
13505 complain);
13508 }
13509 }
13512 {
13515 else
13520 complain);
13521 }
13524 }
13525 }
13527 }
13529 /* Take the tree structure T and replace template parameters used
13530 therein with the argument vector ARGS. IN_DECL is an associated
13531 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
13532 Issue error and warning messages under control of COMPLAIN. Note
13533 that we must be relatively non-tolerant of extensions here, in
13534 order to preserve conformance; if we allow substitutions that
13535 should not be allowed, we may allow argument deductions that should
13536 not succeed, and therefore report ambiguous overload situations
13537 where there are none. In theory, we could allow the substitution,
13538 but indicate that it should have failed, and allow our caller to
13539 make sure that the right thing happens, but we don't try to do this
13540 yet.
13542 This function is used for dealing with types, decls and the like;
13543 for expressions, use tsubst_expr or tsubst_copy. */
13545 tree
13547 {
13570 else
13575 /* Reuse typedefs. We need to do this to handle dependent attributes,
13576 such as attribute aligned. */
13579 {
13583 {
13584 /* DECL represents an alias template and we want to
13585 instantiate it. */
13589 }
13593 {
13597 }
13602 else
13603 /* The typedef is from a non-template context. */
13607 {
13609 r = cp_build_qualified_type_real
13613 }
13614 else
13615 {
13616 /* We don't have an instantiation yet, so drop the typedef. */
13621 }
13622 }
13639 {
13665 {
13671 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
13672 needed. */
13678 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
13679 with TREE_SIDE_EFFECTS that indicates this is not an integral
13680 constant expression. */
13683 {
13686 }
13689 }
13695 {
13701 /* Early in template argument deduction substitution, we don't
13702 want to reduce the level of 'auto', or it will be confused
13703 with a normal template parm in subsequent deduction. */
13715 {
13719 {
13720 /* See through ARGUMENT_PACK_SELECT arguments. */
13722 /* If the selected argument is an expansion E, that most
13723 likely means we were called from
13724 gen_elem_of_pack_expansion_instantiation during the
13725 substituting of pack an argument pack (which Ith
13726 element is a pack expansion, where I is
13727 ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
13728 In this case, the Ith element resulting from this
13729 substituting is going to be a pack expansion, which
13730 pattern is the pattern of E. Let's return the
13731 pattern of E, and
13732 gen_elem_of_pack_expansion_instantiation will
13733 build the resulting pack expansion from it. */
13735 {
13736 /* Make sure we aren't throwing away arg info. */
13739 }
13740 }
13741 }
13746 {
13748 /* If ARG is an argument pack, we don't actually want to
13749 perform a substitution here, because substitutions
13750 for argument packs are only done
13751 element-by-element. We can get to this point when
13752 substituting the type of a non-type template
13753 parameter pack, when that type actually contains
13754 template parameter packs from an outer template, e.g.,
13756 template<typename... Types> struct A {
13757 template<Types... Values> struct B { };
13758 }; */
13762 {
13768 return cp_build_qualified_type_real
13770 }
13772 {
13773 /* We are processing a type constructed from a
13774 template template parameter. */
13785 /* Consider this code:
13787 template <template <class> class Template>
13788 struct Internal {
13789 template <class Arg> using Bind = Template<Arg>;
13790 };
13792 template <template <class> class Template, class Arg>
13793 using Instantiate = Template<Arg>; //#0
13795 template <template <class> class Template,
13796 class Argument>
13797 using Bind =
13798 Instantiate<Internal<Template>::template Bind,
13799 Argument>; //#1
13801 When #1 is parsed, the
13802 BOUND_TEMPLATE_TEMPLATE_PARM representing the
13803 parameter `Template' in #0 matches the
13804 UNBOUND_CLASS_TEMPLATE representing the argument
13805 `Internal<Template>::template Bind'; We then want
13806 to assemble the type `Bind<Argument>' that can't
13807 be fully created right now, because
13808 `Internal<Template>' not being complete, the Bind
13809 template cannot be looked up in that context. So
13810 we need to "store" `Bind<Argument>' for later
13811 when the context of Bind becomes complete. Let's
13812 store that in a TYPENAME_TYPE. */
13816 argvec),
13817 typename_type,
13818 complain);
13820 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
13821 are resolving nested-types in the signature of a
13822 member function templates. Otherwise ARG is a
13823 TEMPLATE_DECL and is the real template to be
13824 instantiated. */
13832 complain);
13833 return cp_build_qualified_type_real
13835 }
13838 else
13839 /* TEMPLATE_PARM_INDEX. */
13841 }
13844 /* This can happen during the attempted tsubst'ing in
13845 unify. This means that we don't yet have any information
13846 about the template parameter in question. */
13849 /* If we get here, we must have been looking at a parm for a
13850 more deeply nested template. Make a new version of this
13851 template parameter, but with a lower level. */
13853 {
13858 {
13860 r = cp_build_qualified_type_real
13864 }
13871 /* Break infinite recursion when substituting the constraints
13873 else
13874 {
13885 {
13886 /* Propagate constraints on placeholders. */
13891 {
13895 }
13896 }
13899 /* We have reduced the level of the template
13900 template parameter, but not the levels of its
13901 template parameters, so canonical_type_parameter
13902 will not be able to find the canonical template
13903 template parameter for this level. Thus, we
13904 require structural equality checking to compare
13905 TEMPLATE_TEMPLATE_PARMs. */
13909 else
13913 {
13915 /* We might need to substitute into the types of non-type
13916 template parameters. */
13928 }
13929 }
13933 /* OK, now substitute the type of the non-type parameter. We
13934 couldn't do it earlier because it might be an auto parameter,
13935 and we wouldn't need to if we had an argument. */
13944 }
13947 }
13950 {
13958 {
13962 }
13965 {
13969 }
13972 {
13976 }
13982 }
13985 /* We should never be tsubsting a binfo. */
13989 /* A vector of template arguments. */
13995 {
13999 /* [temp.deduct]
14001 Type deduction may fail for any of the following
14002 reasons:
14004 -- Attempting to create a pointer to reference type.
14005 -- Attempting to create a reference to a reference type or
14006 a reference to void.
14008 Core issue 106 says that creating a reference to a reference
14009 during instantiation is no longer a cause for failure. We
14010 only enforce this check in strict C++98 mode. */
14014 {
14017 /* We keep track of the last time we issued this error
14018 message to avoid spewing a ton of messages during a
14019 single bad template instantiation. */
14022 {
14027 else
14030 }
14033 }
14037 {
14039 {
14042 type);
14043 else
14045 type);
14046 }
14048 }
14050 {
14054 }
14056 /* In C++0x, during template argument substitution, when there is an
14057 attempt to create a reference to a reference type, reference
14058 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
14060 "If a template-argument for a template-parameter T names a type
14061 that is a reference to a type A, an attempt to create the type
14062 'lvalue reference to cv T' creates the type 'lvalue reference to
14063 A,' while an attempt to create the type type rvalue reference to
14064 cv T' creates the type T"
14065 */
14066 r = cp_build_reference_type
14069 else
14074 /* Will this ever be needed for TYPE_..._TO values? */
14078 }
14080 {
14083 {
14084 /* [temp.deduct]
14086 Type deduction may fail for any of the following
14087 reasons:
14089 -- Attempting to create "pointer to member of T" when T
14090 is not a class type. */
14094 }
14096 {
14100 }
14102 {
14106 }
14109 {
14110 /* The type of the implicit object parameter gets its
14111 cv-qualifiers from the FUNCTION_TYPE. */
14112 tree memptr;
14113 tree method_type
14118 complain);
14119 }
14120 else
14123 complain);
14124 }
14127 {
14128 tree fntype;
14129 tree specs;
14134 /* Substitute the exception specification. */
14142 }
14144 {
14149 /* As an optimization, we avoid regenerating the array type if
14150 it will obviously be the same as T. */
14154 /* These checks should match the ones in create_array_type_for_decl.
14156 [temp.deduct]
14158 The deduction may fail for any of the following reasons:
14160 -- Attempting to create an array with an element type that
14161 is void, a function type, or a reference type, or [DR337]
14162 an abstract class type. */
14168 {
14172 }
14180 {
14183 }
14186 }
14189 {
14201 {
14205 }
14207 {
14208 /* Normally, make_typename_type does not require that the CTX
14209 have complete type in order to allow things like:
14211 template <class T> struct S { typename S<T>::X Y; };
14213 But, such constructs have already been resolved by this
14214 point, so here CTX really should have complete type, unless
14215 it's a partial instantiation. */
14218 {
14222 }
14223 }
14230 {
14233 }
14236 {
14238 {
14242 else
14244 }
14246 {
14250 else
14252 }
14253 }
14255 return cp_build_qualified_type_real
14257 }
14260 {
14272 }
14275 {
14276 tree type;
14292 complain);
14293 }
14296 {
14297 tree type;
14308 {
14310 {
14314 }
14317 }
14328 else
14329 {
14333 /* In a template ~id could be either a complement expression
14334 or an unqualified-id naming a destructor; if instantiating
14335 it produces an expression, it's not an id-expression or
14336 member access. */
14339 }
14344 }
14347 {
14351 }
14355 {
14356 tree r;
14360 else
14368 }
14383 /* We should use one of the expression tsubsts for these codes. */
14389 }
14390 }
14392 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
14393 expression on the left-hand side of the "." or "->" operator. We
14394 only do the lookup if we had a dependent BASELINK. Otherwise we
14395 adjust it onto the instantiated heirarchy. */
14397 static tree
14400 {
14412 {
14419 }
14426 {
14432 /* Treat as-if non-dependent below. */
14437 {
14443 }
14447 }
14448 else
14449 {
14451 /* We're going to overwrite pieces below, make a duplicate. */
14453 }
14455 /* If lookup found a single function, mark it as used at this point.
14456 (If lookup found multiple functions the one selected later by
14457 overload resolution will be marked as used at that point.) */
14463 {
14464 /* Add back the template arguments, if present. */
14469 /* Update the conversion operator type. */
14471 }
14477 {
14479 qualifying_scope,
14480 object_type);
14482 /* We need to call adjust_result_of_qualified_name_lookup in case the
14483 destructor names a base class, but we unset BASELINK_QUALIFIED_P
14484 so that we still get virtual function binding. */
14486 }
14489 }
14491 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
14492 true if the qualified-id will be a postfix-expression in-and-of
14493 itself; false if more of the postfix-expression follows the
14494 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
14495 of "&". */
14497 static tree
14501 {
14502 tree expr;
14503 tree scope;
14504 tree name;
14506 tree template_args;
14511 /* Figure out what name to look up. */
14514 {
14524 }
14525 else
14526 {
14529 }
14531 /* Substitute into the qualifying scope. When there are no ARGS, we
14532 are just trying to simplify a non-dependent expression. In that
14533 case the qualifying scope may be dependent, and, in any case,
14534 substituting will not help. */
14537 {
14540 }
14541 else
14545 {
14552 }
14555 {
14557 {
14558 /* A BIT_NOT_EXPR is used to represent a destructor. */
14560 {
14564 }
14565 else
14568 }
14569 else
14573 {
14575 {
14579 }
14581 }
14582 }
14585 {
14587 scope);
14588 /* Remember that there was a reference to this entity. */
14591 }
14594 {
14600 }
14603 {
14606 complain);
14607 else
14609 }
14615 {
14616 expr = (adjust_result_of_qualified_name_lookup
14618 expr = (finish_qualified_id_expr
14622 }
14624 /* Expressions do not generally have reference type. */
14626 /* However, if we're about to form a pointer-to-member, we just
14627 want the referenced member referenced. */
14635 }
14637 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
14638 initializer, DECL is the substituted VAR_DECL. Other arguments are as
14639 for tsubst. */
14641 static tree
14644 {
14651 {
14652 /* If we had an initializer but it
14653 instantiated to nothing,
14654 value-initialize the object. This will
14655 only occur when the initializer was a
14656 pack expansion where the parameter packs
14657 used in that expansion were of length
14658 zero. */
14660 complain);
14665 }
14668 }
14670 /* Like tsubst, but deals with expressions. This function just replaces
14671 template parms; to finish processing the resultant expression, use
14672 tsubst_copy_and_build or tsubst_expr. */
14674 static tree
14676 {
14678 tree r;
14686 {
14691 {
14692 /* We get here for a use of 'this' in an NSDMI. */
14696 /* This can happen for a parameter name used later in a function
14697 declaration (such as in a late-specified return type). Just
14698 make a dummy decl, since it's only used for its type. */
14701 /* Give it the template pattern as its context; its true context
14702 hasn't been instantiated yet and this is good enough for
14703 mangling. */
14705 }
14714 {
14715 tree enum_type;
14716 tree v;
14720 /* There is no need to substitute into namespace-scope
14721 enumerators. */
14724 /* If ARGS is NULL, then T is known to be non-dependent. */
14728 /* Unfortunately, we cannot just call lookup_name here.
14729 Consider:
14731 template <int I> int f() {
14732 enum E { a = I };
14733 struct S { void g() { E e = a; } };
14734 };
14736 When we instantiate f<7>::S::g(), say, lookup_name is not
14737 clever enough to find f<7>::a. */
14738 enum_type
14748 /* We didn't find the name. That should never happen; if
14749 name-lookup found it during preliminary parsing, we
14750 should find it again here during instantiation. */
14752 }
14757 {
14758 /* Check for a local specialization set up by
14759 tsubst_pack_expansion. */
14761 {
14765 }
14767 /* When retrieving a capture pack from a generic lambda, remove the
14768 lambda call op's own template argument list from ARGS. Only the
14769 template arguments active for the closure type should be used to
14770 retrieve the pack specialization. */
14776 /* Otherwise return the full NONTYPE_ARGUMENT_PACK that
14777 tsubst_decl put in the hash table. */
14779 }
14782 {
14783 tree ctx;
14788 {
14791 {
14795 }
14797 }
14798 }
14808 {
14811 {
14812 /* First try name lookup to find the instantiation. */
14815 {
14816 /* Make sure that the one we found is the one we want. */
14820 }
14824 else
14825 {
14826 /* This can happen for a variable used in a
14827 late-specified return type of a local lambda, or for a
14828 local static or constant. Building a new VAR_DECL
14829 should be OK in all those cases. */
14832 /* Avoid infinite recursion (79640). */
14835 {
14836 /* We can't call cp_finish_decl, so handle the
14837 initializer by hand. */
14852 }
14859 }
14860 /* Remember this for subsequent uses. */
14863 }
14864 }
14865 else
14875 /* An OVERLOAD will always be a non-dependent overload set; an
14876 overload set from function scope will just be represented with an
14877 IDENTIFIER_NODE, and from class scope with a BASELINK. */
14879 /* We must have marked any lookups as persistent. */
14895 {
14896 /* Template template argument like the following example need
14897 special treatment:
14899 template <template <class> class TT> struct C {};
14900 template <class T> struct D {
14901 template <class U> struct E {};
14902 C<E> c; // #1
14903 };
14904 D<int> d; // #2
14906 We are processing the template argument `E' in #1 for
14907 the template instantiation #2. Originally, `E' is a
14908 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
14909 have to substitute this with one having context `D<int>'. */
14913 {
14914 /* When rewriting a constructor into a deduction guide, a
14915 non-dependent name can become dependent, so memtmpl<args>
14916 becomes context::template memtmpl<args>. */
14920 }
14922 }
14923 else
14924 /* Ordinary template template argument. */
14935 {
14939 }
14944 {
14953 /* We only want to compute the number of arguments. */
14956 else
14963 {
14965 /* Set TREE_USED for the benefit of -Wunused. */
14969 }
14977 {
14982 else
14988 else
14991 }
14992 else
14994 }
14996 {
15004 }
15005 /* Fall through */
15021 {
15025 }
15028 {
15029 tree object;
15030 tree name;
15035 {
15039 }
15042 {
15052 }
15057 in_decl);
15058 else
15061 }
15099 {
15103 }
15106 {
15111 }
15114 {
15118 }
15121 {
15129 }
15135 {
15142 }
15145 {
15152 }
15155 {
15162 }
15165 {
15166 /* Substituted template arguments */
15175 }
15178 {
15198 }
15223 /* Fall through. */
15226 {
15229 }
15230 else
15234 /* This is handled by tsubst_copy_and_build. */
15238 {
15242 }
15245 /* We shouldn't have built any of these during initial template
15246 generation. Instead, they should be built during instantiation
15247 in response to the saved STMT_IS_FULL_EXPR_P setting. */
15251 {
15261 }
15279 {
15280 /* Instantiate any typedefs in the type. */
15285 }
15288 /* These can sometimes show up in a partial instantiation, but never
15289 involve template parms. */
15305 /* ??? There's no point in copying it for now, but maybe some
15306 day it will contain more information, such as a pointer back
15307 to the containing function, inlined copy or so. */
15311 /* We shouldn't get here, but keep going if !flag_checking. */
15315 }
15316 }
15318 /* Helper function for tsubst_omp_clauses, used for instantiation of
15319 OMP_CLAUSE_DECL of clauses. */
15321 static tree
15323 tree in_decl)
15324 {
15328 /* Handle an OpenMP array section represented as a TREE_LIST (or
15329 OMP_CLAUSE_DEPEND_KIND). An OMP_CLAUSE_DEPEND (with a depend
15330 kind of OMP_CLAUSE_DEPEND_SINK) can also be represented as a
15331 TREE_LIST. We can handle it exactly the same as an array section
15332 (purpose, value, and a chain), even though the nomenclature
15333 (low_bound, length, etc) is different. */
15335 {
15336 tree low_bound
15342 in_decl);
15351 }
15354 /* Undo convert_from_reference tsubst_expr could have called. */
15360 }
15362 /* Like tsubst_copy, but specifically for OpenMP clauses. */
15364 static tree
15367 {
15372 {
15378 {
15381 {
15387 }
15388 /* FALLTHRU */
15403 in_decl);
15435 {
15438 {
15445 }
15446 else
15448 }
15451 in_decl);
15457 in_decl);
15465 in_decl);
15467 {
15470 }
15475 else
15478 in_decl,
15502 }
15505 {
15515 /* tsubst_expr on SCOPE_REF results in returning
15516 finish_non_static_data_member result. Undo that here. */
15520 {
15525 {
15529 CASE_CONVERT:
15538 /* FALLTHRU */
15542 }
15543 }
15549 {
15552 {
15555 }
15556 }
15560 }
15561 }
15565 {
15570 {
15573 }
15574 }
15576 }
15578 /* Like tsubst_copy_and_build, but unshare TREE_LIST nodes. */
15580 static tree
15582 tree in_decl)
15583 {
15584 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
15604 {
15607 else
15608 {
15612 }
15613 }
15618 #undef RECUR
15619 }
15621 /* Used to temporarily communicate the list of #pragma omp parallel
15622 clauses to #pragma omp for instantiation if they are combined
15623 together. */
15627 /* Substitute one OMP_FOR iterator. */
15629 static void
15634 {
15635 #define RECUR(NODE) \
15636 tsubst_expr ((NODE), args, complain, in_decl, \
15637 integral_constant_expression_p)
15644 {
15647 }
15653 {
15654 /* We need to jump through some hoops to handle declarations in the
15655 init-statement, since we might need to handle auto deduction,
15656 but we need to keep control of initialization. */
15660 }
15661 else
15662 {
15664 {
15667 {
15671 {
15675 CASE_CONVERT:
15683 {
15686 }
15687 /* FALLTHRU */
15691 }
15692 }
15693 }
15694 else
15696 }
15707 {
15709 {
15710 /* Declare the variable, but don't let that initialize it. */
15715 }
15720 {
15725 }
15726 else
15733 }
15736 {
15737 /* Declare and initialize the variable. */
15740 }
15742 {
15746 {
15748 {
15754 {
15757 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
15762 }
15765 {
15767 decl);
15769 }
15772 {
15774 decl);
15776 }
15777 else
15779 }
15782 }
15784 {
15789 {
15792 }
15793 }
15794 }
15797 {
15801 }
15802 else
15806 {
15817 {
15825 }
15826 else
15832 {
15838 }
15842 {
15850 }
15851 else
15857 }
15863 #undef RECUR
15864 }
15866 /* Helper function of tsubst_expr, find OMP_TEAMS inside
15867 of OMP_TARGET's body. */
15869 static tree
15871 {
15874 {
15883 }
15885 }
15887 /* Helper function for tsubst_expr. For decomposition declaration
15888 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
15889 also the corresponding decls representing the identifiers
15890 of the decomposition declaration. Return DECL if successful
15891 or error_mark_node otherwise, set *FIRST to the first decl
15892 in the list chained through DECL_CHAIN and *CNT to the number
15893 of such decls. */
15895 static tree
15899 {
15904 decl2
15909 {
15911 {
15914 }
15931 {
15934 }
15935 else
15937 }
15940 }
15942 /* Like tsubst_copy for expressions, etc. but also does semantic
15943 processing. */
15945 tree
15948 {
15949 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15950 #define RECUR(NODE) \
15951 tsubst_expr ((NODE), args, complain, in_decl, \
15952 integral_constant_expression_p)
15955 tree r;
15956 location_t loc;
15968 {
15970 {
15971 tree_stmt_iterator i;
15975 }
15990 else
16000 {
16002 tree init;
16008 {
16018 else
16020 }
16022 {
16023 /* Don't build up decls for a variadic capture proxy, we'll
16024 instantiate the elements directly as needed. */
16026 }
16029 {
16030 /* We're in tsubst_lambda_expr, we've already inserted a new
16031 capture proxy, so look it up and register it. */
16037 }
16040 /* Don't copy the old closure; we'll create a new one in
16041 tsubst_lambda_expr. */
16043 else
16044 {
16048 {
16049 /* By marking the declaration as instantiated, we avoid
16050 trying to instantiate it. Since instantiate_decl can't
16051 handle local variables, and since we've already done
16052 all that needs to be done, that's the right thing to
16053 do. */
16058 /* Anonymous aggregates are a special case. */
16061 {
16064 {
16068 }
16070 }
16076 {
16081 }
16082 else
16083 {
16088 {
16089 /* For __PRETTY_FUNCTION__ we have to adjust the
16090 initializer. */
16094 }
16095 else
16099 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
16104 {
16106 tree first;
16107 tree ndecl
16115 }
16116 else
16118 }
16119 }
16120 }
16123 }
16133 {
16137 }
16142 {
16149 const unsigned short unroll
16152 {
16154 tree first;
16159 }
16160 else
16167 }
16174 {
16178 }
16184 {
16188 }
16201 else
16202 {
16209 }
16215 {
16224 }
16232 else
16240 else
16261 {
16268 }
16272 {
16274 tree label;
16281 }
16287 /* Computed goto's must be tsubst'd into. On the other hand,
16288 non-computed gotos must not be; the identifier in question
16289 will have no binding. */
16291 else
16297 {
16313 }
16318 {
16323 }
16324 else
16325 {
16330 else
16337 else
16343 else
16345 }
16349 {
16353 {
16355 /* Prevent instantiate_decl from trying to instantiate
16356 this variable. We've already done all that needs to be
16357 done. */
16360 }
16365 }
16371 {
16372 /* Local classes are not independent templates; they are
16373 instantiated along with their containing function. And this
16374 way we don't have to deal with pushing out of one local class
16375 to instantiate a member of another local class. */
16376 /* Closures are handled by the LAMBDA_EXPR. */
16386 }
16390 {
16391 tree condition;
16394 condition =
16396 args,
16405 }
16411 in_decl);
16446 {
16459 in_decl);
16461 {
16468 }
16480 integral_constant_expression_p);
16491 else
16492 {
16500 }
16504 }
16509 /* FALLTHRU */
16516 in_decl);
16533 in_decl);
16544 {
16547 {
16548 /* For combined target teams, ensure the num_teams and
16549 thread_limit clause expressions are evaluated on the host,
16550 before entering the target construct. */
16551 tree c;
16557 {
16566 OMP_CLAUSE_FIRSTPRIVATE);
16570 }
16571 }
16572 }
16632 {
16637 {
16640 }
16646 }
16647 else
16648 {
16655 {
16658 }
16661 {
16666 {
16669 }
16675 }
16676 else
16677 {
16681 }
16684 }
16688 {
16694 {
16698 {
16703 }
16707 }
16708 else
16709 {
16714 }
16715 }
16719 {
16723 }
16736 /* If the first operand was a statement, we're done with it. */
16740 complain));
16754 integral_constant_expression_p));
16755 }
16758 out:
16761 #undef RECUR
16762 #undef RETURN
16763 }
16765 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
16766 function. For description of the body see comment above
16767 cp_parser_omp_declare_reduction_exprs. */
16769 static void
16771 {
16777 tree_stmt_iterator tsi;
16788 {
16807 }
16809 {
16829 }
16830 }
16832 /* T is a postfix-expression that is not being used in a function
16833 call. Return the substituted version of T. */
16835 static tree
16837 tsubst_flags_t complain,
16838 tree in_decl)
16839 {
16843 else
16849 }
16851 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
16852 instantiation context. Instantiating a pack expansion containing a lambda
16853 might result in multiple lambdas all based on the same lambda in the
16854 template. */
16856 tree
16858 {
16872 else
16880 {
16892 else
16897 {
16906 }
16907 else
16908 {
16914 }
16915 }
16919 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
16937 else
16938 {
16939 /* Fix the type of 'this'. */
16945 {
16949 }
16950 else
16951 {
16955 }
16957 /* Let finish_function set this. */
16978 /* The capture list was built up in reverse order; fix that now. */
16985 }
16992 }
16994 /* Like tsubst but deals with expressions and performs semantic
16995 analysis. FUNCTION_P is true if T is the "F" in "F (ARGS)". */
16997 tree
16999 tree args,
17000 tsubst_flags_t complain,
17001 tree in_decl,
17004 {
17005 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
17006 #define RECUR(NODE) \
17007 tsubst_copy_and_build (NODE, args, complain, in_decl, \
17009 integral_constant_expression_p)
17012 location_t loc;
17021 /* N3276 decltype magic only applies to calls at the top level or on the
17022 right side of a comma. */
17027 {
17030 /* Fall through. */
17032 {
17033 tree decl;
17034 cp_id_kind idk;
17039 {
17042 }
17044 /* Look up the name. */
17047 /* By convention, expressions use ERROR_MARK_NODE to indicate
17048 failure, not NULL_TREE. */
17054 integral_constant_expression_p,
17062 input_location);
17066 {
17070 }
17072 }
17075 {
17076 tree object;
17086 {
17091 }
17097 {
17100 }
17101 else
17108 else
17110 }
17113 {
17117 {
17118 /* A type conversion to reference type will be enclosed in
17119 such an indirect ref, but the substitution of the cast
17120 will have also added such an indirect ref. */
17122 }
17123 else
17131 }
17134 {
17138 }
17141 {
17145 {
17150 }
17152 /* We'll pass this to convert_nontype_argument again, we don't need
17153 to actually perform any conversion here. */
17159 flags));
17160 }
17163 {
17167 }
17174 {
17175 tree type;
17181 {
17186 }
17193 {
17211 }
17214 }
17248 else
17250 in_decl);
17285 {
17292 tree r = build_x_binary_op
17294 op0,
17296 ? ERROR_MARK
17298 op1,
17300 ? ERROR_MARK
17308 }
17311 {
17315 }
17331 /* Fall through */
17334 {
17335 tree r;
17341 {
17342 /* When there are no ARGS, we are trying to evaluate a
17343 non-dependent expression from the parser. Trying to do
17344 the substitutions may not work. */
17347 }
17348 else
17349 {
17354 else
17357 /*integral_constant_expression_p=*/
17361 }
17365 else
17369 {
17371 {
17373 {
17377 }
17378 else
17382 }
17384 }
17386 }
17389 {
17399 }
17415 {
17419 tree r = build_x_modify_expr
17422 /* TREE_NO_WARNING must be set if either the expression was
17423 parenthesized or it uses an operator such as >>= rather
17424 than plain assignment. In the former case, it was already
17425 set and must be copied. In the latter case,
17426 build_x_modify_expr sets it and it must not be reset
17427 here. */
17432 }
17437 /* Remember that there was a reference to this entity. */
17444 {
17449 tree ret;
17453 else
17454 {
17458 }
17460 /* If there was an initializer in the original tree, but it
17461 instantiated to an empty list, then we should pass a
17462 non-NULL empty vector to tell build_new that it was an
17463 empty initializer() rather than no initializer. This can
17464 only happen when the initializer is a pack expansion whose
17465 parameter packs are of length zero. */
17468 else
17469 {
17473 else
17474 {
17477 }
17478 }
17484 complain);
17492 }
17495 {
17501 complain));
17502 }
17505 {
17509 integral_constant_expression_p);
17511 op0,
17514 }
17517 {
17518 tree function;
17523 tree ret;
17526 /* Internal function with no arguments. */
17530 /* When we parsed the expression, we determined whether or
17531 not Koenig lookup should be performed. */
17534 {
17537 }
17539 {
17544 }
17546 {
17547 /* Do nothing; calling tsubst_copy_and_build on an identifier
17548 would incorrectly perform unqualified lookup again.
17550 Note that we can also have an IDENTIFIER_NODE if the earlier
17551 unqualified lookup found a member function; in that case
17552 koenig_p will be false and we do want to do the lookup
17553 again to find the instantiated member function.
17555 FIXME but doing that causes c++/15272, so we need to stop
17556 using IDENTIFIER_NODE in that situation. */
17558 }
17559 else
17560 {
17562 {
17568 }
17569 else
17574 /* Avoid error about taking the address of a constructor. */
17578 in_decl,
17580 integral_constant_expression_p);
17584 }
17589 {
17594 else
17595 {
17596 /* Expand the pack expansion and push each entry onto
17597 CALL_ARGS. */
17600 {
17605 {
17610 }
17611 }
17612 else
17613 {
17614 /* A partial substitution. Add one entry. */
17616 }
17617 }
17618 }
17620 /* We do not perform argument-dependent lookup if normal
17621 lookup finds a non-function, in accordance with the
17622 expected resolution of DR 218. */
17625 /* If lookup found a member function, the Koenig lookup is
17626 not appropriate, even if an unqualified-name was used
17627 to denote the function. */
17630 /* Only do this when substitution turns a dependent call
17631 into a non-dependent call. */
17639 {
17641 {
17642 /* For backwards compatibility and good diagnostics, try
17643 the unqualified lookup again if we aren't in SFINAE
17644 context. */
17645 tree unq = (tsubst_copy_and_build
17647 integral_constant_expression_p));
17649 {
17652 }
17655 {
17656 /* In a lambda fn, we have to be careful to not
17657 introduce new this captures. Legacy code can't
17658 be using lambdas anyway, so it's ok to be
17659 stricter. */
17664 "and no declarations were found by "
17665 "argument-dependent lookup at the point "
17672 else
17676 {
17687 {
17689 input_location);
17691 "declarations in dependent base %qT are "
17697 else
17701 }
17702 else
17704 "%qD declared here, later in the "
17707 {
17710 }
17711 }
17714 }
17715 }
17717 {
17722 }
17723 }
17725 /* Remember that there was a reference to this entity. */
17729 {
17732 }
17734 /* Put back tf_decltype for the actual call. */
17739 {
17743 {
17745 "wrong number of arguments to "
17748 }
17749 else
17751 input_location),
17756 /* Unsupported internal function with arguments. */
17758 }
17761 complain);
17763 {
17778 complain);
17779 else
17780 ret = (build_new_method_call
17785 complain));
17786 }
17787 else
17790 koenig_p,
17791 complain);
17796 {
17802 {
17808 {
17810 /* The thunk location is not interesting. */
17812 }
17813 }
17814 }
17817 }
17820 {
17826 {
17828 {
17833 }
17834 else
17835 {
17840 }
17842 }
17843 else
17844 {
17847 }
17851 }
17854 {
17859 input_location));
17860 }
17863 {
17871 {
17872 /* We have pack expansions, so expand those and
17873 create a new list out of it. */
17876 tree chain;
17879 /* Expand the argument expressions. */
17887 /* Build the rest of the list. */
17892 /* Determine the number of arguments. */
17894 {
17897 }
17900 else
17901 {
17902 /* Since we only performed a partial substitution into
17903 the argument pack, we only RETURN (a single list
17904 node. */
17911 }
17913 /* Convert the argument vectors into a TREE_LIST */
17916 {
17917 /* Grab the Ith values. */
17918 i--;
17921 value
17925 /* Build the list (backwards). */
17927 }
17930 }
17946 }
17949 {
17950 tree object;
17951 tree object_type;
17952 tree member;
17953 tree r;
17957 /* Remember that there was a reference to this entity. */
17968 else
17974 {
17979 }
17983 {
17985 {
17990 {
17993 }
17995 {
18000 }
18001 }
18002 }
18005 {
18006 /* Lookup the template functions now that we know what the
18007 scope is. */
18015 {
18018 args);
18019 member = (adjust_result_of_qualified_name_lookup
18021 object_type));
18022 }
18023 else
18024 {
18026 input_location);
18028 }
18029 }
18033 {
18035 {
18039 else
18042 }
18044 }
18048 complain);
18052 }
18059 {
18067 tree r;
18072 /* digest_init will do the wrong thing if we let it. */
18076 /* We do not want to process the index of aggregate
18077 initializers as they are identifier nodes which will be
18078 looked up by digest_init. */
18084 {
18086 /* An identifier index is looked up in the type
18087 being initialized, not the current scope. */
18092 {
18093 /* Substitute into the pack expansion. */
18095 in_decl);
18099 ;
18101 /* Just move the argument into place. */
18103 else
18104 {
18105 /* Update the length of the final CONSTRUCTOR
18106 arguments vector, and note that we will need to
18107 copy.*/
18110 }
18111 }
18112 else
18114 }
18117 {
18122 {
18124 {
18129 }
18130 else
18132 }
18133 }
18139 {
18144 }
18148 }
18151 {
18154 {
18157 }
18158 else
18159 {
18162 }
18163 }
18169 {
18170 /* We don't build decls for an instantiation of a
18171 variadic capture proxy, we instantiate the elements
18172 when needed. */
18175 }
18176 /* Fall through */
18179 {
18181 /* ??? We're doing a subset of finish_id_expression here. */
18183 && !processing_template_decl
18184 && !cp_unevaluated_operand
18187 {
18189 /* Replace an evaluated use of the thread_local variable with
18190 a call to its wrapper. */
18192 }
18197 /* If the original type was a reference, we'll be wrapped in
18198 the appropriate INDIRECT_REF. */
18201 }
18204 {
18208 }
18211 {
18212 tree object_ptr
18219 }
18226 {
18237 }
18240 {
18246 integral_constant_expression_p);
18250 /* If the resulting list of expression statement is empty,
18251 fold it further into void_node. */
18256 }
18259 {
18263 }
18266 /* We can get here for a constant initializer of non-dependent type.
18267 FIXME stop folding in cp_parser_initializer_clause. */
18268 {
18270 complain);
18272 }
18276 integral_constant_expression_p));
18282 {
18287 complain));
18288 }
18294 /* Handle Objective-C++ constructs, if appropriate. */
18295 {
18296 tree subst
18301 }
18303 }
18305 #undef RECUR
18306 #undef RETURN
18307 out:
18310 }
18312 /* Verify that the instantiated ARGS are valid. For type arguments,
18313 make sure that the type's linkage is ok. For non-type arguments,
18314 make sure they are constants if they are integral or enumerations.
18315 Emit an error under control of COMPLAIN, and return TRUE on error. */
18317 static bool
18319 {
18323 {
18333 }
18335 {
18336 /* [basic.link]: A name with no linkage (notably, the name
18337 of a class or enumeration declared in a local scope)
18338 shall not be used to declare an entity with linkage.
18339 This implies that names with no linkage cannot be used as
18340 template arguments
18342 DR 757 relaxes this restriction for C++0x. */
18347 {
18348 /* DR 488 makes use of a type with no linkage cause
18349 type deduction to fail. */
18351 {
18354 else
18357 }
18359 }
18360 /* In order to avoid all sorts of complications, we do not
18361 allow variably-modified types as template arguments. */
18363 {
18367 }
18368 }
18369 /* Class template and alias template arguments should be OK. */
18371 ;
18372 /* A non-type argument of integral or enumerated type must be a
18373 constant. */
18378 {
18382 }
18384 }
18386 static bool
18388 {
18393 {
18396 }
18400 }
18402 /* We're out of SFINAE context now, so generate diagnostics for the access
18403 errors we saw earlier when instantiating D from TMPL and ARGS. */
18405 static void
18407 {
18419 }
18421 /* Instantiate the indicated variable, function, or alias template TMPL with
18422 the template arguments in TARG_PTR. */
18424 static tree
18426 {
18428 tree fndecl;
18429 tree gen_tmpl;
18430 tree spec;
18438 /* If this function is a clone, handle it specially. */
18440 {
18441 tree spec;
18442 tree clone;
18444 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
18445 DECL_CLONED_FUNCTION. */
18451 /* Look for the clone. */
18455 /* We should always have found the clone by now. */
18458 }
18463 /* Check to see if we already have this specialization. */
18467 /* targ_ptr only has the innermost template args, so add the outer ones
18468 from tmpl, which could be either a partial instantiation or gen_tmpl (in
18469 the case of a non-dependent call within a template definition). */
18470 targ_ptr = (add_outermost_template_args
18472 targ_ptr));
18474 /* It would be nice to avoid hashing here and then again in tsubst_decl,
18475 but it doesn't seem to be on the hot path. */
18484 {
18486 {
18490 }
18492 }
18495 complain))
18498 /* We are building a FUNCTION_DECL, during which the access of its
18499 parameters and return types have to be checked. However this
18500 FUNCTION_DECL which is the desired context for access checking
18501 is not built yet. We solve this chicken-and-egg problem by
18502 deferring all checks until we have the FUNCTION_DECL. */
18505 /* Instantiation of the function happens in the context of the function
18506 template, not the context of the overload resolution we're doing. */
18508 /* If there are dependent arguments, e.g. because we're doing partial
18509 ordering, make sure processing_template_decl stays set. */
18513 {
18517 }
18523 {
18524 /* We need to determine if we're using a partial or explicit
18525 specialization now, because the type of the variable could be
18526 different. */
18532 {
18537 }
18538 }
18540 /* Substitute template parameters to obtain the specialization. */
18548 {
18551 }
18553 /* The DECL_TI_TEMPLATE should always be the immediate parent
18554 template, not the most general template. */
18558 /* Now we know the specialization, compute access previously
18559 deferred. Do no access control for inheriting constructors,
18560 as we already checked access for the inherited constructor. */
18563 {
18568 }
18571 /* If we've just instantiated the main entry point for a function,
18572 instantiate all the alternate entry points as well. We do this
18573 by cloning the instantiation of the main entry point, not by
18574 instantiating the template clones. */
18579 {
18581 {
18582 /* Remember to reinstantiate when we're out of SFINAE so the user
18583 can see the errors. */
18585 }
18587 }
18589 }
18591 /* Wrapper for instantiate_template_1. */
18593 tree
18595 {
18596 tree ret;
18601 }
18603 /* Instantiate the alias template TMPL with ARGS. Also push a template
18604 instantiation level, which instantiate_template doesn't do because
18605 functions and variables have sufficient context established by the
18606 callers. */
18608 static tree
18610 {
18617 {
18620 }
18622 args =
18630 /* We can't free this if a pending_template entry or last_error_tinst_level
18631 is pointing at it. */
18637 }
18639 /* PARM is a template parameter pack for FN. Returns true iff
18640 PARM is used in a deducible way in the argument list of FN. */
18642 static bool
18644 {
18647 {
18649 tree packs;
18655 {
18656 /* The template parameter pack is used in a function parameter
18657 pack. If this is the end of the parameter list, the
18658 template parameter pack is deducible. */
18661 else
18662 /* Otherwise, not. Well, it could be deduced from
18663 a non-pack parameter, but doing so would end up with
18664 a deduction mismatch, so don't bother. */
18666 }
18667 }
18668 /* The template parameter pack isn't used in any function parameter
18669 packs, but it might be used deeper, e.g. tuple<Args...>. */
18671 }
18673 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
18674 NARGS elements of the arguments that are being used when calling
18675 it. TARGS is a vector into which the deduced template arguments
18676 are placed.
18678 Returns either a FUNCTION_DECL for the matching specialization of FN or
18679 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
18680 true, diagnostics will be printed to explain why it failed.
18682 If FN is a conversion operator, or we are trying to produce a specific
18683 specialization, RETURN_TYPE is the return type desired.
18685 The EXPLICIT_TARGS are explicit template arguments provided via a
18686 template-id.
18688 The parameter STRICT is one of:
18690 DEDUCE_CALL:
18691 We are deducing arguments for a function call, as in
18692 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
18693 deducing arguments for a call to the result of a conversion
18694 function template, as in [over.call.object].
18696 DEDUCE_CONV:
18697 We are deducing arguments for a conversion function, as in
18698 [temp.deduct.conv].
18700 DEDUCE_EXACT:
18701 We are deducing arguments when doing an explicit instantiation
18702 as in [temp.explicit], when determining an explicit specialization
18703 as in [temp.expl.spec], or when taking the address of a function
18704 template, as in [temp.deduct.funcaddr]. */
18706 tree
18708 tree explicit_targs,
18709 tree targs,
18712 tree return_type,
18713 unification_kind_t strict,
18717 {
18718 tree parms;
18719 tree fntype;
18732 tree tinst;
18738 full_targs = (add_outermost_template_args
18740 targs));
18745 /* In C++0x, it's possible to have a function template whose type depends
18746 on itself recursively. This is most obvious with decltype, but can also
18747 occur with enumeration scope (c++/48969). So we need to catch infinite
18748 recursion and reject the substitution at deduction time; this function
18749 will return error_mark_node for any repeated substitution.
18751 This also catches excessive recursion such as when f<N> depends on
18752 f<N-1> across all integers, and returns error_mark_node for all the
18753 substitutions back up to the initial one.
18755 This is, of course, not reentrant. */
18765 {
18766 /* [temp.deduct]
18768 The specified template arguments must match the template
18769 parameters in kind (i.e., type, nontype, template), and there
18770 must not be more arguments than there are parameters;
18771 otherwise type deduction fails.
18773 Nontype arguments must match the types of the corresponding
18774 nontype template parameters, or must be convertible to the
18775 types of the corresponding nontype parameters as specified in
18776 _temp.arg.nontype_, otherwise type deduction fails.
18778 All references in the function type of the function template
18779 to the corresponding template parameters are replaced by the
18780 specified template argument values. If a substitution in a
18781 template parameter or in the function type of the function
18782 template results in an invalid type, type deduction fails. */
18793 explicit_targs);
18795 /* Adjust any explicit template arguments before entering the
18796 substitution context. */
18797 explicit_targs
18799 complain,
18805 /* Substitute the explicit args into the function type. This is
18806 necessary so that, for instance, explicitly declared function
18807 arguments can match null pointed constants. If we were given
18808 an incomplete set of explicit args, we must not do semantic
18809 processing during substitution as we could create partial
18810 instantiations. */
18812 {
18817 /* Dig out the actual parm. */
18820 {
18823 }
18825 {
18828 }
18831 /* No explicit argument for this template parameter. */
18835 {
18836 /* Mark the argument pack as "incomplete". We could
18837 still deduce more arguments during unification.
18838 We remove this mark in type_unification_real. */
18840 {
18844 }
18846 /* We have some incomplete argument packs. */
18848 }
18849 }
18853 {
18856 }
18859 /* Ignore any access checks; we'll see them again in
18860 instantiate_template and they might have the wrong
18861 access path at this point. */
18873 /* Place the explicitly specified arguments in TARGS. */
18877 }
18879 /* Never do unification on the 'this' parameter. */
18883 {
18884 /* We're deducing for a call to the result of a template conversion
18885 function. The parms we really want are in return_type. */
18889 }
18891 {
18900 }
18902 /* We allow incomplete unification without an error message here
18903 because the standard doesn't seem to explicitly prohibit it. Our
18904 callers must be ready to deal with unification failures in any
18905 event. */
18908 /* If we aren't explaining yet, push tinst context so we can see where
18909 any errors (e.g. from class instantiations triggered by instantiation
18910 of default template arguments) come from. If we are explaining, this
18911 context is redundant. */
18913 {
18916 }
18918 /* type_unification_real will pass back any access checks from default
18919 template argument substitution. */
18931 /* Now that we have bindings for all of the template arguments,
18932 ensure that the arguments deduced for the template template
18933 parameters have compatible template parameter lists. We cannot
18934 check this property before we have deduced all template
18935 arguments, because the template parameter types of a template
18936 template parameter might depend on prior template parameters
18937 deduced after the template template parameter. The following
18938 ill-formed example illustrates this issue:
18940 template<typename T, template<T> class C> void f(C<5>, T);
18942 template<int N> struct X {};
18944 void g() {
18945 f(X<5>(), 5l); // error: template argument deduction fails
18946 }
18948 The template parameter list of 'C' depends on the template type
18949 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
18950 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
18951 time that we deduce 'C'. */
18954 {
18957 }
18959 /* All is well so far. Now, check:
18961 [temp.deduct]
18963 When all template arguments have been deduced, all uses of
18964 template parameters in nondeduced contexts are replaced with
18965 the corresponding deduced argument values. If the
18966 substitution results in an invalid type, as described above,
18967 type deduction fails. */
18970 {
18973 }
18975 /* Also collect access checks from the instantiation. */
18988 /* Now perform any access checks encountered during substitution. */
18995 /* If we're looking for an exact match, check that what we got
18996 is indeed an exact match. It might not be if some template
18997 parameters are used in non-deduced contexts. But don't check
18998 for an exact match if we have dependent template arguments;
18999 in that case we're doing partial ordering, and we already know
19000 that we have two candidates that will provide the actual type. */
19002 {
19006 tree sarg
19012 {
19016 }
19017 }
19019 /* After doing deduction with the inherited constructor, actually return an
19020 instantiation of the inheriting constructor. */
19026 fail:
19029 {
19031 /* Reset once we're all the way out. */
19033 }
19035 /* We can't free this if a pending_template entry or last_error_tinst_level
19036 is pointing at it. */
19042 }
19044 /* Adjust types before performing type deduction, as described in
19045 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
19046 sections are symmetric. PARM is the type of a function parameter
19047 or the return type of the conversion function. ARG is the type of
19048 the argument passed to the call, or the type of the value
19049 initialized with the result of the conversion function.
19050 ARG_EXPR is the original argument expression, which may be null. */
19052 static int
19056 tree arg_expr)
19057 {
19061 {
19066 /* Swap PARM and ARG throughout the remainder of this
19067 function; the handling is precisely symmetric since PARM
19068 will initialize ARG rather than vice versa. */
19073 /* Core issue #873: Do the DR606 thing (see below) for these cases,
19074 too, but here handle it by stripping the reference from PARM
19075 rather than by adding it to ARG. */
19083 /* Nothing else to do in this case. */
19088 }
19091 {
19092 /* [temp.deduct.call]
19094 If P is not a reference type:
19096 --If A is an array type, the pointer type produced by the
19097 array-to-pointer standard conversion (_conv.array_) is
19098 used in place of A for type deduction; otherwise,
19100 --If A is a function type, the pointer type produced by
19101 the function-to-pointer standard conversion
19102 (_conv.func_) is used in place of A for type deduction;
19103 otherwise,
19105 --If A is a cv-qualified type, the top level
19106 cv-qualifiers of A's type are ignored for type
19107 deduction. */
19112 else
19114 }
19116 /* [14.8.2.1/3 temp.deduct.call], "A forwarding reference is an rvalue
19117 reference to a cv-unqualified template parameter that does not represent a
19118 template parameter of a class template (during class template argument
19119 deduction (13.3.1.8)). If P is a forwarding reference and the argument is
19120 an lvalue, the type "lvalue reference to A" is used in place of A for type
19121 deduction. */
19128 /* try_one_overload doesn't provide an arg_expr, but
19129 functions are always lvalues. */
19133 /* [temp.deduct.call]
19135 If P is a cv-qualified type, the top level cv-qualifiers
19136 of P's type are ignored for type deduction. If P is a
19137 reference type, the type referred to by P is used for
19138 type deduction. */
19141 {
19144 }
19146 /* DR 322. For conversion deduction, remove a reference type on parm
19147 too (which has been swapped into ARG). */
19152 }
19154 /* Subroutine of unify_one_argument. PARM is a function parameter of a
19155 template which does contain any deducible template parameters; check if
19156 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
19157 unify_one_argument. */
19159 static int
19162 {
19163 tree type;
19167 else
19174 {
19178 }
19180 {
19185 }
19189 else
19191 }
19195 /* Returns true iff the expression EXPR is one from which a template
19196 argument can be deduced. In other words, if it's an undecorated
19197 use of a template non-type parameter. */
19199 static bool
19201 {
19202 /* Strip implicit conversions. */
19206 }
19208 /* Returns true iff the array domain DOMAIN uses a template parameter in a
19209 deducible way; that is, if it has a max value of <PARM> - 1. */
19211 static bool
19213 {
19222 }
19224 /* Returns true iff the template arguments ARGS use a template parameter
19225 in a deducible way. */
19227 static bool
19229 {
19231 {
19236 else
19237 {
19244 else
19246 }
19249 }
19251 }
19253 /* Returns true iff TYPE contains any deducible references to template
19254 parameters, as per 14.8.2.5. */
19256 static bool
19258 {
19262 /* T
19263 cv-list T
19264 TT<T>
19265 TT<i>
19266 TT<> */
19271 /* T*
19272 T&
19273 T&& */
19277 /* T[integer-constant ]
19278 type [i] */
19283 /* T type ::*
19284 type T::*
19285 T T::*
19286 T (type ::*)()
19287 type (T::*)()
19288 type (type ::*)(T)
19289 type (T::*)(T)
19290 T (type ::*)(T)
19291 T (T::*)()
19292 T (T::*)(T) */
19295 || (uses_deducible_template_parms
19298 /* template-name <T> (where template-name refers to a class template)
19299 template-name <i> (where template-name refers to a class template) */
19306 /* type (T)
19307 T()
19308 T(T) */
19311 {
19320 }
19323 }
19325 /* Subroutine of type_unification_real and unify_pack_expansion to
19326 handle unification of a single P/A pair. Parameters are as
19327 for those functions. */
19329 static int
19333 {
19340 /* We can't deduce anything from this, but we might get all the
19341 template args from other function args. */
19344 /* Implicit conversions (Clause 4) will be performed on a function
19345 argument to convert it to the type of the corresponding function
19346 parameter if the parameter type contains no template-parameters that
19347 participate in template argument deduction. */
19350 /* For function parameters with no deducible template parameters,
19351 just return. We'll check non-dependent conversions later. */
19355 {
19357 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
19358 | UNIFY_ALLOW_MORE_CV_QUAL
19372 }
19374 /* We only do these transformations if this is the top-level
19375 parameter_type_list in a call or declaration matching; in other
19376 situations (nested function declarators, template argument lists) we
19377 won't be comparing a type to an expression, and we don't do any type
19378 adjustments. */
19380 {
19382 {
19385 {
19386 /* [temp.deduct.type] A template-argument can be
19387 deduced from a pointer to function or pointer
19388 to member function argument if the set of
19389 overloaded functions does not contain function
19390 templates and at most one of a set of
19391 overloaded functions provides a unique
19392 match. */
19396 /* If a unique match was not found, this is a
19397 non-deduced context, so we still succeed. */
19399 }
19405 }
19407 arg_strict |=
19409 }
19410 else
19415 /* For deduction from an init-list we need the actual list. */
19419 }
19421 /* for_each_template_parm callback that always returns 0. */
19423 static int
19425 {
19427 }
19429 /* for_each_template_parm any_fn callback to handle deduction of a template
19430 type argument from the type of an array bound. */
19432 static int
19434 {
19442 {
19448 }
19450 /* Keep walking. */
19452 }
19454 /* Try to deduce any not-yet-deduced template type arguments from the type of
19455 an array bound. This is handled separately from unify because 14.8.2.5 says
19456 "The type of a type parameter is only deduced from an array bound if it is
19457 not otherwise deduced." */
19459 static void
19461 {
19466 }
19468 /* Most parms like fn_type_unification.
19470 If SUBR is 1, we're being called recursively (to unify the
19471 arguments of a function or method parameter of a function
19472 template).
19474 CHECKS is a pointer to a vector of access checks encountered while
19475 substituting default template arguments. */
19477 static int
19479 tree full_targs,
19480 tree xparms,
19484 unification_kind_t strict,
19488 {
19493 tree parms;
19504 /* Reset the number of non-defaulted template arguments contained
19505 in TARGS. */
19508 again:
19516 {
19521 /* For a function parameter pack that occurs at the end of the
19522 parameter-declaration-list, the type A of each remaining
19523 argument of the call is compared with the type P of the
19524 declarator-id of the function parameter pack. */
19530 /* For a function parameter pack that does not occur at the
19531 end of the parameter-declaration-list, the type of the
19532 parameter pack is a non-deduced context. */
19539 explain_p))
19541 }
19546 {
19547 /* Unify the remaining arguments with the pack expansion type. */
19548 tree argvec;
19551 /* Allocate a TREE_VEC and copy in all of the arguments */
19556 /* Copy the parameter into parmvec. */
19562 /* Advance to the end of the list of parameters. */
19564 }
19566 /* Fail if we've reached the end of the parm list, and more args
19567 are present, and the parm list isn't variadic. */
19570 /* Fail if parms are left and they don't have default values and
19571 they aren't all deduced as empty packs (c++/57397). This is
19572 consistent with sufficient_parms_p. */
19575 {
19579 do
19580 {
19583 count++;
19585 }
19589 type_pack_p);
19590 }
19593 {
19594 tsubst_flags_t complain = (explain_p
19595 ? tf_warning_or_error
19600 {
19604 /* Clear the "incomplete" flags on all argument packs now so that
19605 substituting them into later default arguments works. */
19607 {
19610 }
19618 {
19623 }
19625 /* If this is an undeduced nontype parameter that depends on
19626 a type parameter, try another pass; its type may have been
19627 deduced from a later argument than the one from which
19628 this parameter can be deduced. */
19632 {
19635 }
19637 /* Core issue #226 (C++0x) [temp.deduct]:
19639 If a template argument has not been deduced, its
19640 default template argument, if any, is used.
19642 When we are in C++98 mode, TREE_PURPOSE will either
19643 be NULL_TREE or ERROR_MARK_NODE, so we do not need
19644 to explicitly check cxx_dialect here. */
19646 /* OK, there is a default argument. Wait until after the
19647 conversion check to do substitution. */
19650 /* If the type parameter is a parameter pack, then it will
19651 be deduced to an empty parameter pack. */
19653 {
19654 tree arg;
19657 {
19660 }
19661 else
19668 }
19671 }
19673 /* DR 1391: All parameters have args, now check non-dependent parms for
19674 convertibility. */
19678 {
19684 /* For a function parameter pack that occurs at the end of the
19685 parameter-declaration-list, the type A of each remaining
19686 argument of the call is compared with the type P of the
19687 declarator-id of the function parameter pack. */
19693 /* For a function parameter pack that does not occur at the
19694 end of the parameter-declaration-list, the type of the
19695 parameter pack is a non-deduced context. */
19704 explain_p))
19706 }
19708 /* Now substitute into the default template arguments. */
19710 {
19734 else
19742 {
19744 /* The position of the first default template argument,
19745 is also the number of non-defaulted arguments in TARGS.
19746 Record that. */
19749 }
19750 }
19754 }
19760 }
19762 /* Subroutine of type_unification_real. Args are like the variables
19763 at the call site. ARG is an overloaded function (or template-id);
19764 we try deducing template args from each of the overloads, and if
19765 only one succeeds, we go with that. Modifies TARGS and returns
19766 true on success. */
19768 static bool
19770 tree targs,
19771 tree parm,
19772 tree arg,
19773 unification_kind_t strict,
19776 {
19783 {
19786 }
19787 else
19791 /* Handle `&x' where `x' is some static or non-static member
19792 function name. */
19798 /* Strip baselink information. */
19803 {
19804 /* If we got some explicit template args, we need to plug them into
19805 the affected templates before we try to unify, in case the
19806 explicit args will completely resolve the templates in question. */
19813 {
19826 {
19831 {
19834 }
19835 }
19838 }
19839 /* If no templates (or more than one) are fully resolved by the
19840 explicit arguments, this template-id is a non-deduced context; it
19841 could still be OK if we deduce all template arguments for the
19842 enclosing call through other arguments. */
19845 }
19848 /* If ARG is, for example, "(0, &f)" then its type will be unknown
19849 -- but the deduction does not succeed because the expression is
19850 not just the function on its own. */
19852 else
19854 {
19859 {
19862 }
19863 }
19865 /* [temp.deduct.type] A template-argument can be deduced from a pointer
19866 to function or pointer to member function argument if the set of
19867 overloaded functions does not contain function templates and at most
19868 one of a set of overloaded functions provides a unique match.
19870 So if we found multiple possibilities, we return success but don't
19871 deduce anything. */
19874 {
19878 {
19883 /* Don't forget explicit template arguments in a pack. */
19887 }
19888 }
19893 }
19895 /* Core DR 115: In contexts where deduction is done and fails, or in
19896 contexts where deduction is not done, if a template argument list is
19897 specified and it, along with any default template arguments, identifies
19898 a single function template specialization, then the template-id is an
19899 lvalue for the function template specialization. */
19901 tree
19903 {
19916 {
19919 }
19921 {
19924 }
19926 {
19929 }
19932 {
19936 /* If we got some explicit template args, we need to plug them into
19937 the affected templates before we try to unify, in case the
19938 explicit args will completely resolve the templates in question. */
19946 {
19959 {
19962 {
19965 }
19967 {
19970 }
19971 }
19972 }
19974 {
19982 {
19983 tree base
19986 }
19990 }
19992 /* There were no good options and at least one bad one, so let the
19993 user know what the problem is. */
19995 }
19997 }
19999 /* Subroutine of resolve_overloaded_unification; does deduction for a single
20000 overload. Fills TARGS with any deduced arguments, or error_mark_node if
20001 different overloads deduce different arguments for a given parm.
20002 ADDR_P is true if the expression for which deduction is being
20003 performed was of the form "& fn" rather than simply "fn".
20005 Returns 1 on success. */
20007 static int
20009 tree orig_targs,
20010 tree targs,
20011 tree parm,
20012 tree arg,
20013 unification_kind_t strict,
20017 {
20019 tree tempargs;
20025 /* [temp.deduct.type] A template-argument can be deduced from a pointer
20026 to function or pointer to member function argument if the set of
20027 overloaded functions does not contain function templates and at most
20028 one of a set of overloaded functions provides a unique match.
20030 So if this is a template, just return success. */
20042 /* We don't copy orig_targs for this because if we have already deduced
20043 some template args from previous args, unify would complain when we
20044 try to deduce a template parameter for the same argument, even though
20045 there isn't really a conflict. */
20052 /* First make sure we didn't deduce anything that conflicts with
20053 explicitly specified args. */
20055 {
20062 /* Since we're unifying against ourselves, we will fill in
20063 template args used in the function parm list with our own
20064 template parms. Discard them. */
20067 {
20068 /* Check that the argument at each index of the deduced argument pack
20069 is equivalent to the corresponding explicitly specified argument.
20070 We may have deduced more arguments than were explicitly specified,
20071 and that's OK. */
20073 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
20074 that's wrong if we deduce the same argument pack from multiple
20075 function arguments: it's only incomplete the first time. */
20088 }
20091 }
20094 {
20099 }
20102 }
20104 /* PARM is a template class (perhaps with unbound template
20105 parameters). ARG is a fully instantiated type. If ARG can be
20106 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
20107 TARGS are as for unify. */
20109 static tree
20112 {
20113 tree copy_of_targs;
20123 /* We need to make a new template argument vector for the call to
20124 unify. If we used TARGS, we'd clutter it up with the result of
20125 the attempted unification, even if this class didn't work out.
20126 We also don't want to commit ourselves to all the unifications
20127 we've already done, since unification is supposed to be done on
20128 an argument-by-argument basis. In other words, consider the
20129 following pathological case:
20131 template <int I, int J, int K>
20132 struct S {};
20134 template <int I, int J>
20135 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
20137 template <int I, int J, int K>
20138 void f(S<I, J, K>, S<I, I, I>);
20140 void g() {
20141 S<0, 0, 0> s0;
20142 S<0, 1, 2> s2;
20144 f(s0, s2);
20145 }
20147 Now, by the time we consider the unification involving `s2', we
20148 already know that we must have `f<0, 0, 0>'. But, even though
20149 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
20150 because there are two ways to unify base classes of S<0, 1, 2>
20151 with S<I, I, I>. If we kept the already deduced knowledge, we
20152 would reject the possibility I=1. */
20156 {
20160 }
20162 /* If unification failed, we're done. */
20168 }
20170 /* Given a template type PARM and a class type ARG, find the unique
20171 base type in ARG that is an instance of PARM. We do not examine
20172 ARG itself; only its base-classes. If there is not exactly one
20173 appropriate base class, return NULL_TREE. PARM may be the type of
20174 a partial specialization, as well as a plain template type. Used
20175 by unify. */
20177 static enum template_base_result
20180 {
20182 tree binfo;
20188 {
20189 /* The type could not be completed. */
20192 }
20194 /* Walk in inheritance graph order. The search order is not
20195 important, and this avoids multiple walks of virtual bases. */
20197 {
20202 {
20203 /* If there is more than one satisfactory baseclass, then:
20205 [temp.deduct.call]
20207 If they yield more than one possible deduced A, the type
20208 deduction fails.
20210 applies. */
20212 {
20215 }
20218 }
20219 }
20223 }
20225 /* Returns the level of DECL, which declares a template parameter. */
20227 static int
20229 {
20231 {
20241 }
20243 }
20245 /* Decide whether ARG can be unified with PARM, considering only the
20246 cv-qualifiers of each type, given STRICT as documented for unify.
20247 Returns nonzero iff the unification is OK on that basis. */
20249 static int
20251 {
20257 {
20258 /* Although a CVR qualifier is ignored when being applied to a
20259 substituted template parameter ([8.3.2]/1 for example), that
20260 does not allow us to unify "const T" with "int&" because both
20261 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
20262 It is ok when we're allowing additional CV qualifiers
20263 at the outer level [14.8.2.1]/3,1st bullet. */
20273 }
20284 }
20286 /* Determines the LEVEL and INDEX for the template parameter PARM. */
20287 void
20289 {
20293 {
20296 }
20297 else
20298 {
20301 }
20302 }
20304 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
20305 do { \
20306 if (unify (TP, TA, P, A, S, EP)) \
20307 return 1; \
20308 } while (0)
20310 /* Unifies the remaining arguments in PACKED_ARGS with the pack
20311 expansion at the end of PACKED_PARMS. Returns 0 if the type
20312 deduction succeeds, 1 otherwise. STRICT is the same as in
20313 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
20314 function call argument list. We'll need to adjust the arguments to make them
20315 types. SUBR tells us if this is from a recursive call to
20316 type_unification_real, or for comparing two template argument
20317 lists. */
20319 static int
20323 {
20324 tree parm
20330 /* Add in any args remembered from an earlier partial instantiation. */
20337 /* Determine the parameter packs we will be deducing from the
20338 pattern, and record their current deductions. */
20341 {
20345 /* Determine the index and level of this parameter pack. */
20348 /* Keep track of the parameter packs and their corresponding
20349 argument packs. */
20352 }
20354 /* Loop through all of the arguments that have not yet been
20355 unified and unify each with the pattern. */
20357 {
20358 tree parm;
20362 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
20363 or the element of its argument pack at the current index if
20364 this argument was explicitly specified. */
20366 {
20375 {
20378 }
20380 }
20382 /* If we had explicit template arguments, substitute them into the
20383 pattern before deduction. */
20385 {
20386 /* Some arguments might still be unspecified or dependent. */
20394 NULL_TREE);
20399 }
20400 else
20403 /* Unify the pattern with the current argument. */
20405 explain_p))
20408 /* For each parameter pack, collect the deduced value. */
20410 {
20416 }
20417 }
20419 /* Verify that the results of unification with the parameter packs
20420 produce results consistent with what we've seen before, and make
20421 the deduced argument packs available. */
20423 {
20430 /* By default keep the original deduced argument pack.
20431 If necessary, more specific code is going to update the
20432 resulting deduced argument later down in this function. */
20436 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
20437 actually deduce anything. */
20445 {
20446 /* If we had fewer function args than explicit template args,
20447 just use the explicits. */
20452 }
20455 {
20456 tree result;
20457 /* Build the deduced *_ARGUMENT_PACK. */
20459 {
20462 }
20463 else
20468 /* Note the deduced argument packs for this parameter
20469 pack. */
20471 }
20475 {
20476 /* We only had the explicitly-provided arguments before, but
20477 now we have a complete set of arguments. */
20483 }
20484 else
20485 {
20491 /* Inconsistent unification of this parameter pack. */
20493 bad_old_arg,
20494 bad_new_arg);
20495 }
20496 }
20499 }
20501 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
20502 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
20503 parameters and return value are as for unify. */
20505 static int
20509 {
20510 tree parm_max;
20511 tree arg_max;
20515 /* Our representation of array types uses "N - 1" as the
20516 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
20517 not an integer constant. We cannot unify arbitrarily
20518 complex expressions, so we eliminate the MINUS_EXPRs
20519 here. */
20523 {
20526 }
20530 {
20531 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
20532 trying to unify the type of a variable with the type
20533 of a template parameter. For example:
20535 template <unsigned int N>
20536 void f (char (&) [N]);
20537 int g();
20538 void h(int i) {
20539 char a[g(i)];
20540 f(a);
20541 }
20543 Here, the type of the ARG will be "int [g(i)]", and
20544 may be a SAVE_EXPR, etc. */
20548 }
20550 /* If only one of the bounds used a MINUS_EXPR, compensate
20551 by adding one to the other bound. */
20554 integer_type_node,
20555 parm_max,
20556 integer_one_node);
20559 integer_type_node,
20560 arg_max,
20561 integer_one_node);
20565 }
20567 /* Returns whether T, a P or A in unify, is a type, template or expression. */
20571 static pa_kind_t
20573 {
20582 else
20584 }
20586 /* Deduce the value of template parameters. TPARMS is the (innermost)
20587 set of template parameters to a template. TARGS is the bindings
20588 for those template parameters, as determined thus far; TARGS may
20589 include template arguments for outer levels of template parameters
20590 as well. PARM is a parameter to a template function, or a
20591 subcomponent of that parameter; ARG is the corresponding argument.
20592 This function attempts to match PARM with ARG in a manner
20593 consistent with the existing assignments in TARGS. If more values
20594 are deduced, then TARGS is updated.
20596 Returns 0 if the type deduction succeeds, 1 otherwise. The
20597 parameter STRICT is a bitwise or of the following flags:
20599 UNIFY_ALLOW_NONE:
20600 Require an exact match between PARM and ARG.
20601 UNIFY_ALLOW_MORE_CV_QUAL:
20602 Allow the deduced ARG to be more cv-qualified (by qualification
20603 conversion) than ARG.
20604 UNIFY_ALLOW_LESS_CV_QUAL:
20605 Allow the deduced ARG to be less cv-qualified than ARG.
20606 UNIFY_ALLOW_DERIVED:
20607 Allow the deduced ARG to be a template base class of ARG,
20608 or a pointer to a template base class of the type pointed to by
20609 ARG.
20610 UNIFY_ALLOW_INTEGER:
20611 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
20612 case for more information.
20613 UNIFY_ALLOW_OUTER_LEVEL:
20614 This is the outermost level of a deduction. Used to determine validity
20615 of qualification conversions. A valid qualification conversion must
20616 have const qualified pointers leading up to the inner type which
20617 requires additional CV quals, except at the outer level, where const
20618 is not required [conv.qual]. It would be normal to set this flag in
20619 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
20620 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
20621 This is the outermost level of a deduction, and PARM can be more CV
20622 qualified at this point.
20623 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
20624 This is the outermost level of a deduction, and PARM can be less CV
20625 qualified at this point. */
20627 static int
20630 {
20632 tree targ;
20633 tree tparm;
20635 tsubst_flags_t complain = (explain_p
20636 ? tf_warning_or_error
20639 /* I don't think this will do the right thing with respect to types.
20640 But the only case I've seen it in so far has been array bounds, where
20641 signedness is the only information lost, and I think that will be
20642 okay. */
20650 /* We can't deduce anything from this, but we might get all the
20651 template args from other function args. */
20657 /* If PARM uses template parameters, then we can't bail out here,
20658 even if ARG == PARM, since we won't record unifications for the
20659 template parameters. We might need them if we're trying to
20660 figure out which of two things is more specialized. */
20664 /* Handle init lists early, so the rest of the function can assume
20665 we're dealing with a type. */
20667 {
20672 /* Replace T with std::initializer_list<T> for deduction. */
20679 /* We can only deduce from an initializer list argument if the
20680 parameter is std::initializer_list or an array; otherwise this
20681 is a non-deduced context. */
20686 else
20687 {
20689 /* Deduction is defined in terms of a single type, so just punt
20690 on the (bizarre) std::initializer_list<T...>. */
20693 }
20696 {
20703 {
20707 /* It should only be possible to get here for a call. */
20709 elt_strict |= maybe_adjust_types_for_deduction
20712 }
20715 explain_p);
20716 }
20720 {
20721 /* Also deduce from the length of the initializer list. */
20728 }
20730 /* If the std::initializer_list<T> deduction worked, replace the
20731 deduced A with std::initializer_list<A>. */
20733 {
20738 }
20740 }
20742 /* If parm and arg aren't the same kind of thing (template, type, or
20743 expression), fail early. */
20747 /* Immediately reject some pairs that won't unify because of
20748 cv-qualification mismatches. */
20751 /* It is the elements of the array which hold the cv quals of an array
20752 type, and the elements might be template type parms. We'll check
20753 when we recurse. */
20755 /* We check the cv-qualifiers when unifying with template type
20756 parameters below. We want to allow ARG `const T' to unify with
20757 PARM `T' for example, when computing which of two templates
20758 is more specialized, for example. */
20772 {
20776 /* In a type which contains a nested-name-specifier, template
20777 argument values cannot be deduced for template parameters used
20778 within the nested-name-specifier. */
20790 /* The PARM is not one we're trying to unify. Just check
20791 to see if it matches ARG. */
20792 {
20797 else
20799 }
20806 /* Check for mixed types and values. */
20814 {
20817 {
20818 /* First try to match ARG directly. */
20820 explain_p);
20822 {
20823 /* Otherwise, look for a suitable base of ARG, as below. */
20830 }
20831 }
20832 /* ARG must be constructed from a template class or a template
20833 template parameter. */
20838 /* Deduce arguments T, i from TT<T> or TT<i>. */
20844 /* Fall through to deduce template name. */
20845 }
20849 {
20850 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
20852 /* Simple cases: Value already set, does match or doesn't. */
20857 }
20858 else
20859 {
20860 /* If PARM is `const T' and ARG is only `int', we don't have
20861 a match unless we are allowing additional qualification.
20862 If ARG is `const int' and PARM is just `T' that's OK;
20863 that binds `const int' to `T'. */
20868 /* Consider the case where ARG is `const volatile int' and
20869 PARM is `const T'. Then, T should be `volatile int'. */
20870 arg = cp_build_qualified_type_real
20875 /* Simple cases: Value already set, does match or doesn't. */
20881 /* Make sure that ARG is not a variable-sized array. (Note
20882 that were talking about variable-sized arrays (like
20883 `int[n]'), rather than arrays of unknown size (like
20884 `int[]').) We'll get very confused by such a type since
20885 the bound of the array is not constant, and therefore
20886 not mangleable. Besides, such types are not allowed in
20887 ISO C++, so we can do as we please here. We do allow
20888 them for 'auto' deduction, since that isn't ABI-exposed. */
20892 /* Strip typedefs as in convert_template_argument. */
20894 }
20896 /* If ARG is a parameter pack or an expansion, we cannot unify
20897 against it unless PARM is also a parameter pack. */
20902 /* If the argument deduction results is a METHOD_TYPE,
20903 then there is a problem.
20904 METHOD_TYPE doesn't map to any real C++ type the result of
20905 the deduction can not be of that type. */
20919 {
20920 /* The PARM is not one we're trying to unify. Just check
20921 to see if it matches ARG. */
20927 }
20933 {
20937 /* We're deducing from an array bound, the type doesn't matter. */
20943 }
20945 /* [temp.deduct.type] If, in the declaration of a function template
20946 with a non-type template-parameter, the non-type
20947 template-parameter is used in an expression in the function
20948 parameter-list and, if the corresponding template-argument is
20949 deduced, the template-argument type shall match the type of the
20950 template-parameter exactly, except that a template-argument
20951 deduced from an array bound may be of any integral type.
20952 The non-type parameter might use already deduced type parameters. */
20957 {
20961 }
20964 /* Template-parameter dependent expression. Just accept it for now.
20965 It will later be processed in convert_template_argument. */
20966 ;
20972 /* Convert the ARG to the type of PARM; the deduced non-type
20973 template argument must exactly match the types of the
20974 corresponding parameter. */
20977 {
20978 /* We haven't deduced the type of this parameter yet. */
20980 /* We deduce from array bounds in try_array_deduction. */
20982 {
20983 /* Deduce it from the non-type argument. */
20988 }
20989 else
20990 /* Try again later. */
20992 }
20993 else
20996 /* If ARG is a parameter pack or an expansion, we cannot unify
20997 against it unless PARM is also a parameter pack. */
21002 {
21005 }
21010 {
21011 /* A pointer-to-member constant can be unified only with
21012 another constant. */
21016 /* Just unify the class member. It would be useless (and possibly
21017 wrong, depending on the strict flags) to unify also
21018 PTRMEM_CST_CLASS, because we want to be sure that both parm and
21019 arg refer to the same variable, even if through different
21020 classes. For instance:
21022 struct A { int x; };
21023 struct B : A { };
21025 Unification of &A::x and &B::x must succeed. */
21028 }
21031 {
21035 /* [temp.deduct.call]
21037 A can be another pointer or pointer to member type that can
21038 be converted to the deduced A via a qualification
21039 conversion (_conv.qual_).
21041 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
21042 This will allow for additional cv-qualification of the
21043 pointed-to types if appropriate. */
21046 /* The derived-to-base conversion only persists through one
21047 level of pointers. */
21052 }
21084 /* We have already checked cv-qualification at the top of the
21085 function. */
21089 /* As far as unification is concerned, this wins. Later checks
21090 will invalidate it if necessary. */
21093 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
21094 /* Type INTEGER_CST can come from ordinary constant template args. */
21106 {
21116 /* Check for pack expansions in the parameters. */
21118 {
21120 {
21122 /* We can unify against something with a trailing
21123 parameter pack. */
21125 else
21126 /* [temp.deduct.type]/9: If the template argument list of
21127 P contains a pack expansion that is not the last
21128 template argument, the entire template argument list
21129 is a non-deduced context. */
21131 }
21132 }
21134 /* If we don't have enough arguments to satisfy the parameters
21135 (not counting the pack expression at the end), or we have
21136 too many arguments for a parameter list that doesn't end in
21137 a pack expression, we can't unify. */
21143 /* Unify all of the parameters that precede the (optional)
21144 pack expression. */
21146 {
21151 }
21154 DEDUCE_EXACT,
21157 }
21165 {
21173 }
21178 {
21182 {
21183 /* First, we try to unify the PARM and ARG directly. */
21188 {
21189 /* Fallback to the special case allowed in
21190 [temp.deduct.call]:
21192 If P is a class, and P has the form
21193 template-id, then A can be a derived class of
21194 the deduced A. Likewise, if P is a pointer to
21195 a class of the form template-id, A can be a
21196 pointer to a derived class pointed to by the
21197 deduced A. */
21203 {
21204 /* Don't give the derived diagnostic if we're
21205 already dealing with the same template. */
21206 bool same_template
21212 }
21213 }
21214 }
21218 /* Perhaps PARM is something like S<U> and ARG is S<int>.
21219 Then, we should unify `int' and `U'. */
21221 else
21222 /* There's no chance of unification succeeding. */
21227 }
21234 {
21237 tree a;
21243 /* CV qualifications for methods can never be deduced, they must
21244 match exactly. We need to check them explicitly here,
21245 because type_unification_real treats them as any other
21246 cv-qualified parameter. */
21248 && (!check_cv_quals_for_unify
21276 {
21288 }
21291 }
21294 /* Unify a pointer to member with a pointer to member function, which
21295 deduces the type of the member as a function type. */
21297 {
21298 /* Check top-level cv qualifiers */
21306 /* Determine the type of the function we are unifying against. */
21310 }
21329 /* Matched cases are handled by the ARG == PARM test above. */
21333 /* We might get a variable as a non-type template argument in parm if the
21334 corresponding parameter is type-dependent. Make any necessary
21335 adjustments based on whether arg is a reference. */
21339 {
21344 }
21345 /* Now use the normal expression code to check whether they match. */
21356 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
21357 or UNDERLYING_TYPE nodes. */
21361 /* Unification fails if we hit an error node. */
21366 {
21376 }
21377 /* FALLTHRU */
21380 /* An unresolved overload is a nondeduced context. */
21384 expr:
21385 /* We must be looking at an expression. This can happen with
21386 something like:
21388 template <int I>
21389 void foo(S<I>, S<I + 2>);
21391 This is a "nondeduced context":
21393 [deduct.type]
21395 The nondeduced contexts are:
21397 --A type that is a template-id in which one or more of
21398 the template-arguments is an expression that references
21399 a template-parameter.
21401 In these cases, we assume deduction succeeded, but don't
21402 actually infer any unifications. */
21407 else
21409 }
21410 }
21411 #undef RECUR_AND_CHECK_FAILURE
21412 \f
21413 /* Note that DECL can be defined in this translation unit, if
21414 required. */
21416 static void
21418 {
21419 tree clone;
21423 }
21425 /* Called if RESULT is explicitly instantiated, or is a member of an
21426 explicitly instantiated class. */
21428 void
21430 {
21433 /* If this entity has already been written out, it's too late to
21434 make any modifications. */
21438 /* For anonymous namespace we don't need to do anything. */
21440 {
21443 }
21446 /* The TREE_PUBLIC flag for function declarations will have been
21447 set correctly by tsubst. */
21450 /* This might have been set by an earlier implicit instantiation. */
21455 else
21456 {
21459 /* Always make artificials weak. */
21462 /* For WIN32 we also want to put explicit instantiations in
21463 linkonce sections. */
21466 }
21468 /* If EXTERN_P, then this function will not be emitted -- unless
21469 followed by an explicit instantiation, at which point its linkage
21470 will be adjusted. If !EXTERN_P, then this function will be
21471 emitted here. In neither circumstance do we want
21472 import_export_decl to adjust the linkage. */
21474 }
21476 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
21477 important template arguments. If any are missing, we check whether
21478 they're important by using error_mark_node for substituting into any
21479 args that were used for partial ordering (the ones between ARGS and END)
21480 and seeing if it bubbles up. */
21482 static bool
21484 {
21489 {
21492 }
21494 {
21498 }
21500 }
21502 /* Given two function templates PAT1 and PAT2, return:
21504 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
21505 -1 if PAT2 is more specialized than PAT1.
21506 0 if neither is more specialized.
21508 LEN indicates the number of parameters we should consider
21509 (defaulted parameters should not be considered).
21511 The 1998 std underspecified function template partial ordering, and
21512 DR214 addresses the issue. We take pairs of arguments, one from
21513 each of the templates, and deduce them against each other. One of
21514 the templates will be more specialized if all the *other*
21515 template's arguments deduce against its arguments and at least one
21516 of its arguments *does* *not* deduce against the other template's
21517 corresponding argument. Deduction is done as for class templates.
21518 The arguments used in deduction have reference and top level cv
21519 qualifiers removed. Iff both arguments were originally reference
21520 types *and* deduction succeeds in both directions, an lvalue reference
21521 wins against an rvalue reference and otherwise the template
21522 with the more cv-qualified argument wins for that pairing (if
21523 neither is more cv-qualified, they both are equal). Unlike regular
21524 deduction, after all the arguments have been deduced in this way,
21525 we do *not* verify the deduced template argument values can be
21526 substituted into non-deduced contexts.
21528 The logic can be a bit confusing here, because we look at deduce1 and
21529 targs1 to see if pat2 is at least as specialized, and vice versa; if we
21530 can find template arguments for pat1 to make arg1 look like arg2, that
21531 means that arg2 is at least as specialized as arg1. */
21533 int
21535 {
21548 /* Remove the this parameter from non-static member functions. If
21549 one is a non-static member function and the other is not a static
21550 member function, remove the first parameter from that function
21551 also. This situation occurs for operator functions where we
21552 locate both a member function (with this pointer) and non-member
21553 operator (with explicit first operand). */
21555 {
21560 }
21562 {
21565 {
21566 len--;
21568 }
21569 }
21571 /* If only one is a conversion operator, they are unordered. */
21575 /* Consider the return type for a conversion function */
21577 {
21580 len++;
21581 }
21583 processing_template_decl++;
21589 /* Stop when an ellipsis is seen. */
21591 {
21602 {
21603 /* When both arguments are pack expansions, we need only
21604 unify the patterns themselves. */
21608 /* This is the last comparison we need to do. */
21610 }
21612 /* DR 1847: If a particular P contains no template-parameters that
21613 participate in template argument deduction, that P is not used to
21614 determine the ordering. */
21620 {
21624 }
21627 {
21631 }
21637 {
21643 /* Setup the parameter vector, which contains only ARG1. */
21646 /* Setup the argument vector, which contains the remaining
21647 arguments. */
21656 /* We cannot deduce in the other direction, because ARG1 is
21657 a pack expansion but ARG2 is not. */
21659 }
21661 {
21667 /* Setup the parameter vector, which contains only ARG1. */
21670 /* Setup the argument vector, which contains the remaining
21671 arguments. */
21680 /* We cannot deduce in the other direction, because ARG2 is
21681 a pack expansion but ARG1 is not.*/
21683 }
21685 else
21686 {
21687 /* The normal case, where neither argument is a pack
21688 expansion. */
21695 }
21697 /* If we couldn't deduce arguments for tparms1 to make arg1 match
21698 arg2, then arg2 is not as specialized as arg1. */
21704 /* "If, for a given type, deduction succeeds in both directions
21705 (i.e., the types are identical after the transformations above)
21706 and both P and A were reference types (before being replaced with
21707 the type referred to above):
21708 - if the type from the argument template was an lvalue reference and
21709 the type from the parameter template was not, the argument type is
21710 considered to be more specialized than the other; otherwise,
21711 - if the type from the argument template is more cv-qualified
21712 than the type from the parameter template (as described above),
21713 the argument type is considered to be more specialized than the other;
21714 otherwise,
21715 - neither type is more specialized than the other." */
21718 {
21720 {
21723 else
21725 }
21727 {
21732 }
21733 }
21736 /* We've failed to deduce something in either direction.
21737 These must be unordered. */
21740 next:
21744 /* We have already processed all of the arguments in our
21745 handing of the pack expansion type. */
21750 }
21752 /* "In most cases, all template parameters must have values in order for
21753 deduction to succeed, but for partial ordering purposes a template
21754 parameter may remain without a value provided it is not used in the
21755 types being used for partial ordering."
21757 Thus, if we are missing any of the targs1 we need to substitute into
21758 origs1, then pat2 is not as specialized as pat1. This can happen when
21759 there is a nondeduced context. */
21765 processing_template_decl--;
21767 /* If both deductions succeed, the partial ordering selects the more
21768 constrained template. */
21770 {
21775 }
21777 /* All things being equal, if the next argument is a pack expansion
21778 for one function but not for the other, prefer the
21779 non-variadic function. FIXME this is bogus; see c++/41958. */
21783 {
21786 }
21792 else
21794 }
21796 /* Determine which of two partial specializations of TMPL is more
21797 specialized.
21799 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
21800 to the first partial specialization. The TREE_PURPOSE is the
21801 innermost set of template parameters for the partial
21802 specialization. PAT2 is similar, but for the second template.
21804 Return 1 if the first partial specialization is more specialized;
21805 -1 if the second is more specialized; 0 if neither is more
21806 specialized.
21808 See [temp.class.order] for information about determining which of
21809 two templates is more specialized. */
21811 static int
21813 {
21814 tree targs;
21823 /* Just like what happens for functions, if we are ordering between
21824 different template specializations, we may encounter dependent
21825 types in the arguments, and we need our dependency check functions
21826 to behave correctly. */
21830 {
21833 }
21837 {
21840 }
21843 /* If both deductions succeed, the partial ordering selects the more
21844 constrained template. */
21848 /* In the case of a tie where at least one of the templates
21849 has a parameter pack at the end, the template with the most
21850 non-packed parameters wins. */
21852 && any_deductions
21855 {
21861 /* We don't count the pack expansion at the end. */
21871 }
21874 }
21876 /* Return the template arguments that will produce the function signature
21877 DECL from the function template FN, with the explicit template
21878 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
21879 also match. Return NULL_TREE if no satisfactory arguments could be
21880 found. */
21882 static tree
21884 {
21888 tree decl_arg_types;
21891 tree arg;
21895 /* Never do unification on the 'this' parameter. */
21916 }
21918 /* Return the innermost template arguments that, when applied to a partial
21919 specialization SPEC_TMPL of TMPL, yield the ARGS.
21921 For example, suppose we have:
21923 template <class T, class U> struct S {};
21924 template <class T> struct S<T*, int> {};
21926 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
21927 partial specialization and the ARGS will be {double*, int}. The resulting
21928 vector will be {double}, indicating that `T' is bound to `double'. */
21930 static tree
21932 {
21934 tree spec_args
21937 tree deduced_args;
21938 tree innermost_deduced_args;
21942 {
21946 innermost_deduced_args);
21947 }
21948 else
21952 again:
21961 {
21963 {
21969 }
21971 }
21975 {
21978 }
21980 /* Verify that nondeduced template arguments agree with the type
21981 obtained from argument deduction.
21983 For example:
21985 struct A { typedef int X; };
21986 template <class T, class U> struct C {};
21987 template <class T> struct C<T, typename T::X> {};
21989 Then with the instantiation `C<A, int>', we can deduce that
21990 `T' is `A' but unify () does not check whether `typename T::X'
21991 is `int'. */
22002 /* We only need to check the innermost arguments; the other
22003 arguments will always agree. */
22008 /* Now that we have bindings for all of the template arguments,
22009 ensure that the arguments deduced for the template template
22010 parameters have compatible template parameter lists. See the use
22011 of template_template_parm_bindings_ok_p in fn_type_unification
22012 for more information. */
22017 }
22019 // Compare two function templates T1 and T2 by deducing bindings
22020 // from one against the other. If both deductions succeed, compare
22021 // constraints to see which is more constrained.
22022 static int
22024 {
22029 {
22032 }
22035 {
22038 }
22040 // If both deductions succeed, then one may be more constrained.
22045 }
22047 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
22048 Return the TREE_LIST node with the most specialized template, if
22049 any. If there is no most specialized template, the error_mark_node
22050 is returned.
22052 Note that this function does not look at, or modify, the
22053 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
22054 returned is one of the elements of INSTANTIATIONS, callers may
22055 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
22056 and retrieve it from the value returned. */
22058 tree
22060 {
22067 {
22073 {
22074 /* Equally specialized, move to next function. If there
22075 is no next function, nothing's most specialized. */
22080 }
22081 }
22084 /* Now verify that champ is better than everything earlier in the
22085 instantiation list. */
22088 {
22091 }
22092 }
22094 processing_template_decl--;
22100 }
22102 /* If DECL is a specialization of some template, return the most
22103 general such template. Otherwise, returns NULL_TREE.
22105 For example, given:
22107 template <class T> struct S { template <class U> void f(U); };
22109 if TMPL is `template <class U> void S<int>::f(U)' this will return
22110 the full template. This function will not trace past partial
22111 specializations, however. For example, given in addition:
22113 template <class T> struct S<T*> { template <class U> void f(U); };
22115 if TMPL is `template <class U> void S<int*>::f(U)' this will return
22116 `template <class T> template <class U> S<T*>::f(U)'. */
22118 tree
22120 {
22122 {
22125 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
22126 template friend, or a FIELD_DECL for a capture pack. */
22129 }
22131 /* Look for more and more general templates. */
22133 {
22134 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
22135 (See cp-tree.h for details.) */
22144 /* Stop if we run into an explicitly specialized class template. */
22151 }
22154 }
22156 /* Return the most specialized of the template partial specializations
22157 which can produce TARGET, a specialization of some class or variable
22158 template. The value returned is actually a TREE_LIST; the TREE_VALUE is
22159 a TEMPLATE_DECL node corresponding to the partial specialization, while
22160 the TREE_PURPOSE is the set of template arguments that must be
22161 substituted into the template pattern in order to generate TARGET.
22163 If the choice of partial specialization is ambiguous, a diagnostic
22164 is issued, and the error_mark_node is returned. If there are no
22165 partial specializations matching TARGET, then NULL_TREE is
22166 returned, indicating that the primary template should be used. */
22168 static tree
22170 {
22172 tree t;
22173 tree champ;
22180 {
22184 }
22186 {
22189 }
22191 {
22195 }
22196 else
22201 /* For determining which partial specialization to use, only the
22202 innermost args are interesting. */
22204 {
22207 }
22210 {
22211 tree spec_args;
22215 {
22216 /* Substitute in the template args from the enclosing class. */
22220 }
22227 {
22231 /* Keep the candidate only if the constraints are satisfied,
22232 or if we're not compiling with concepts. */
22235 {
22238 }
22239 }
22240 }
22250 {
22253 ;
22254 else
22255 {
22257 {
22260 {
22263 }
22264 }
22266 }
22267 }
22271 {
22274 {
22277 }
22278 }
22281 {
22288 else
22292 {
22297 }
22300 }
22303 }
22305 /* Explicitly instantiate DECL. */
22307 void
22309 {
22314 /* An error occurred, for which grokdeclarator has already issued
22315 an appropriate message. */
22318 {
22321 }
22327 {
22328 /* There is an asymmetry here in the way VAR_DECLs and
22329 FUNCTION_DECLs are handled by grokdeclarator. In the case of
22330 the latter, the DECL we get back will be marked as a
22331 template instantiation, and the appropriate
22332 DECL_TEMPLATE_INFO will be set up. This does not happen for
22333 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
22334 should handle VAR_DECLs as it currently handles
22335 FUNCTION_DECLs. */
22337 {
22340 }
22343 {
22346 }
22348 {
22353 }
22354 }
22356 {
22359 }
22360 else
22363 /* Check for various error cases. Note that if the explicit
22364 instantiation is valid the RESULT will currently be marked as an
22365 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
22366 until we get here. */
22369 {
22370 /* DR 259 [temp.spec].
22372 Both an explicit instantiation and a declaration of an explicit
22373 specialization shall not appear in a program unless the explicit
22374 instantiation follows a declaration of the explicit specialization.
22376 For a given set of template parameters, if an explicit
22377 instantiation of a template appears after a declaration of an
22378 explicit specialization for that template, the explicit
22379 instantiation has no effect. */
22381 }
22383 {
22384 /* [temp.spec]
22386 No program shall explicitly instantiate any template more
22387 than once.
22389 We check DECL_NOT_REALLY_EXTERN so as not to complain when
22390 the first instantiation was `extern' and the second is not,
22391 and EXTERN_P for the opposite case. */
22394 /* If an "extern" explicit instantiation follows an ordinary
22395 explicit instantiation, the template is instantiated. */
22398 }
22400 {
22403 }
22405 {
22408 }
22411 ;
22413 {
22416 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
22419 }
22420 else
22428 }
22430 static void
22432 {
22438 {
22441 }
22442 }
22444 /* Called from do_type_instantiation through binding_table_foreach to
22445 do recursive instantiation for the type bound in ENTRY. */
22446 static void
22448 {
22454 }
22456 /* Perform an explicit instantiation of template class T. STORAGE, if
22457 non-null, is the RID for extern, inline or static. COMPLAIN is
22458 nonzero if this is called from the parser, zero if called recursively,
22459 since the standard is unclear (as detailed below). */
22461 void
22463 {
22473 {
22474 tree tmpl =
22478 else
22481 }
22486 {
22489 t);
22491 }
22494 {
22496 {
22498 {
22501 "ISO C++ 1998 forbids the use of %<extern%> on "
22503 }
22504 else
22506 "ISO C++ forbids the use of %qE"
22508 }
22516 else
22517 {
22519 storage);
22521 }
22522 }
22525 {
22526 /* DR 259 [temp.spec].
22528 Both an explicit instantiation and a declaration of an explicit
22529 specialization shall not appear in a program unless the explicit
22530 instantiation follows a declaration of the explicit specialization.
22532 For a given set of template parameters, if an explicit
22533 instantiation of a template appears after a declaration of an
22534 explicit specialization for that template, the explicit
22535 instantiation has no effect. */
22537 }
22539 {
22540 /* [temp.spec]
22542 No program shall explicitly instantiate any template more
22543 than once.
22545 If PREVIOUS_INSTANTIATION_EXTERN_P, then the first explicit
22546 instantiation was `extern'. If EXTERN_P then the second is.
22547 These cases are OK. */
22554 /* If we've already instantiated the template, just return now. */
22557 }
22565 /* In contrast to implicit instantiation, where only the
22566 declarations, and not the definitions, of members are
22567 instantiated, we have here:
22569 [temp.explicit]
22571 The explicit instantiation of a class template specialization
22572 implies the instantiation of all of its members not
22573 previously explicitly specialized in the translation unit
22574 containing the explicit instantiation.
22576 Of course, we can't instantiate member template classes, since we
22577 don't have any arguments for them. Note that the standard is
22578 unclear on whether the instantiation of the members are
22579 *explicit* instantiations or not. However, the most natural
22580 interpretation is that it should be an explicit
22581 instantiation. */
22585 && !static_p
22588 {
22593 }
22598 }
22600 /* Given a function DECL, which is a specialization of TMPL, modify
22601 DECL to be a re-instantiation of TMPL with the same template
22602 arguments. TMPL should be the template into which tsubst'ing
22603 should occur for DECL, not the most general template.
22605 One reason for doing this is a scenario like this:
22607 template <class T>
22608 void f(const T&, int i);
22610 void g() { f(3, 7); }
22612 template <class T>
22613 void f(const T& t, const int i) { }
22615 Note that when the template is first instantiated, with
22616 instantiate_template, the resulting DECL will have no name for the
22617 first parameter, and the wrong type for the second. So, when we go
22618 to instantiate the DECL, we regenerate it. */
22620 static void
22622 {
22623 /* The arguments used to instantiate DECL, from the most general
22624 template. */
22625 tree code_pattern;
22629 /* Make sure that we can see identifiers, and compute access
22630 correctly. */
22634 {
22635 tree decl_parm;
22636 tree pattern_parm;
22637 tree specs;
22651 specs);
22653 /* Merge parameter declarations. */
22656 pattern_parm
22660 {
22661 tree parm_type;
22662 tree attributes;
22667 NULL_TREE);
22673 {
22676 }
22679 }
22680 /* Merge any parameters that match with the function parameter
22681 pack. */
22683 {
22685 tree expanded_types;
22686 /* Expand the TYPE_PACK_EXPANSION that provides the types for
22687 the parameters in this function parameter pack. */
22692 {
22693 tree parm_type;
22694 tree attributes;
22697 /* Rename the parameter to include the index. */
22706 {
22709 }
22711 }
22712 }
22713 /* Merge additional specifiers from the CODE_PATTERN. */
22717 }
22719 {
22729 }
22730 else
22734 }
22736 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
22737 substituted to get DECL. */
22739 tree
22741 {
22744 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
22745 for the instantiation. This is not always the most general
22746 template. Consider, for example:
22748 template <class T>
22749 struct S { template <class U> void f();
22750 template <> void f<int>(); };
22752 and an instantiation of S<double>::f<int>. We want TD to be the
22753 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
22755 more general template. */
22757 /* We must also deal with friend templates. Given:
22759 template <class T> struct S {
22760 template <class U> friend void f() {};
22761 };
22763 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
22764 so far as the language is concerned, but that's still
22765 where we get the pattern for the instantiation from. On
22766 other hand, if the definition comes outside the class, say:
22768 template <class T> struct S {
22769 template <class U> friend void f();
22770 };
22771 template <class U> friend void f() {}
22773 we don't need to look any further. That's what the check for
22774 DECL_INITIAL is for. */
22778 {
22779 /* The present template, TD, should not be a definition. If it
22780 were a definition, we should be using it! Note that we
22781 cannot restructure the loop to just keep going until we find
22782 a template with a definition, since that might go too far if
22783 a specialization was declared, but not defined. */
22785 /* Fetch the more general template. */
22787 }
22790 }
22792 /* Returns true if we need to instantiate this template instance even if we
22793 know we aren't going to emit it. */
22795 bool
22797 {
22798 /* We always instantiate inline functions so that we can inline them. An
22799 explicit instantiation declaration prohibits implicit instantiation of
22800 non-inline functions. With high levels of optimization, we would
22801 normally inline non-inline functions -- but we're not allowed to do
22802 that for "extern template" functions. Therefore, we check
22803 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
22807 /* And we need to instantiate static data members so that
22808 their initializers are available in integral constant
22809 expressions. */
22812 }
22814 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
22815 instantiate it now, modifying TREE_TYPE (fn). Returns false on
22816 error, true otherwise. */
22818 bool
22820 {
22823 /* Don't instantiate a noexcept-specification from template context. */
22838 {
22844 {
22845 /* If hash_set::add returns true, the element was already there. */
22850 fn);
22852 }
22854 {
22869 }
22870 else
22880 }
22883 {
22886 else
22888 }
22891 }
22893 /* We're starting to process the function INST, an instantiation of PATTERN;
22894 add their parameters to local_specializations. */
22896 static void
22898 {
22902 {
22906 }
22908 {
22910 {
22913 }
22914 else
22915 {
22916 /* Register the (value) argument pack as a specialization of
22917 TMPL_PARM, then move on. */
22920 }
22921 }
22923 }
22925 /* Produce the definition of D, a _DECL generated from a template. If
22926 DEFER_OK is true, then we don't have to actually do the
22927 instantiation now; we just have to do it sometime. Normally it is
22928 an error if this is an explicit instantiation but D is undefined.
22929 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
22930 instantiated class template. */
22932 tree
22934 {
22936 tree gen_args;
22937 tree args;
22938 tree td;
22939 tree code_pattern;
22940 tree spec;
22941 tree gen_tmpl;
22949 /* This function should only be used to instantiate templates for
22950 functions and static member variables. */
22953 /* A concept is never instantiated. */
22956 /* Variables are never deferred; if instantiation is required, they
22957 are instantiated right away. That allows for better code in the
22958 case that an expression refers to the value of the variable --
22959 if the variable has a constant value the referring expression can
22960 take advantage of that fact. */
22964 /* Don't instantiate cloned functions. Instead, instantiate the
22965 functions they cloned. */
22973 /* D has already been instantiated or explicitly specialized, so
22974 there's nothing for us to do here.
22976 It might seem reasonable to check whether or not D is an explicit
22977 instantiation, and, if so, stop here. But when an explicit
22978 instantiation is deferred until the end of the compilation,
22979 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
22980 the instantiation. */
22983 /* Check to see whether we know that this template will be
22984 instantiated in some other file, as with "extern template"
22985 extension. */
22988 /* In general, we do not instantiate such templates. */
22996 /* We should already have the extra args. */
22999 /* And what's in the hash table should match D. */
23003 /* This needs to happen before any tsubsting. */
23009 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
23010 for the instantiation. */
23015 {
23016 /* Look up an explicit specialization, if any. */
23020 {
23023 }
23024 }
23028 /* We should never be trying to instantiate a member of a class
23029 template or partial specialization. */
23034 /* In the case of a friend template whose definition is provided
23035 outside the class, we may have too many arguments. Drop the
23036 ones we don't need. The same is true for specializations. */
23037 args = get_innermost_template_args
23041 {
23047 }
23048 else
23049 {
23054 else
23056 }
23058 /* We may be in the middle of deferred access check. Disable it now. */
23061 /* Unless an explicit instantiation directive has already determined
23062 the linkage of D, remember that a definition is available for
23063 this entity. */
23073 /* If D is a member of an explicitly instantiated class template,
23074 and no definition is available, treat it like an implicit
23075 instantiation. */
23078 {
23079 /* Leave linkage flags alone on instantiations with anonymous
23080 visibility. */
23082 {
23085 }
23087 }
23089 /* Defer all other templates, unless we have been explicitly
23090 forbidden from doing so. */
23092 template. */
23093 ! pattern_defined
23094 /* If it's OK to postpone instantiation, do so. */
23095 || defer_ok
23096 /* If this is a static data member that will be defined
23097 elsewhere, we don't want to instantiate the entire data
23098 member, but we do want to instantiate the initializer so that
23099 we can substitute that elsewhere. */
23101 /* Handle here a deleted function too, avoid generating
23102 its body (c++/61080). */
23104 {
23105 /* The definition of the static data member is now required so
23106 we must substitute the initializer. */
23110 {
23111 tree ns;
23112 tree init;
23121 args,
23124 /* If instantiating the initializer involved instantiating this
23125 again, don't call cp_finish_decl twice. */
23127 {
23128 /* Make sure the initializer is still constant, in case of
23129 circular dependency (template/instantiate6.C). */
23130 const_init
23134 LOOKUP_ONLYCONVERTING);
23135 }
23139 }
23141 /* We restore the source position here because it's used by
23142 add_pending_template. */
23148 /* [temp.explicit]
23150 The definition of a non-exported function template, a
23151 non-exported member function template, or a non-exported
23152 member function or static data member of a class template
23153 shall be present in every translation unit in which it is
23154 explicitly instantiated. */
23158 /* If we're in unevaluated context, we just wanted to get the
23159 constant value; this isn't an odr use, so don't queue
23160 a full instantiation. */
23163 /* ??? Historically, we have instantiated inline functions, even
23164 when marked as "extern template". */
23168 }
23169 /* Tell the repository that D is available in this translation unit
23170 -- and see if it is supposed to be instantiated here. */
23172 {
23173 /* In a PCH file, despite the fact that the repository hasn't
23174 requested instantiation in the PCH it is still possible that
23175 an instantiation will be required in a file that includes the
23176 PCH. */
23179 /* Instantiate inline functions so that the inliner can do its
23180 job, even though we'll not be emitting a copy of this
23181 function. */
23184 }
23187 tree fn_context;
23198 else
23199 {
23203 }
23205 /* Mark D as instantiated so that recursive calls to
23206 instantiate_decl do not try to instantiate it again. */
23209 /* Regenerate the declaration in case the template has been modified
23210 by a subsequent redeclaration. */
23213 /* We already set the file and line above. Reset them now in case
23214 they changed as a result of calling regenerate_decl_from_template. */
23218 {
23219 tree init;
23222 /* Clear out DECL_RTL; whatever was there before may not be right
23223 since we've reset the type of the declaration. */
23227 /* The initializer is placed in DECL_INITIAL by
23228 regenerate_decl_from_template so we don't need to
23229 push/pop_access_scope again here. Pull it out so that
23230 cp_finish_decl can process it. */
23235 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
23236 initializer. That function will defer actual emission until
23237 we have a chance to determine linkage. */
23240 /* Enter the scope of D so that access-checking works correctly. */
23253 }
23257 {
23258 /* Set up the list of local specializations. */
23262 /* Set up context. */
23266 else
23269 /* Some typedefs referenced from within the template code need to be
23270 access checked at template instantiation time, i.e now. These
23271 types were added to the template at parsing time. Let's get those
23272 and perform the access checks then. */
23274 args);
23276 /* Create substitution entries for the parameters. */
23279 /* Substitute into the body of the function. */
23283 else
23284 {
23289 /* Set the current input_location to the end of the function
23290 so that finish_function knows where we are. */
23291 input_location
23294 /* Remember if we saw an infinite loop in the template. */
23295 current_function_infinite_loop
23297 }
23299 /* Finish the function. */
23303 else
23304 {
23307 }
23311 }
23313 /* We're not deferring instantiation any more. */
23318 else
23324 out:
23333 }
23335 /* Run through the list of templates that we wish we could
23336 instantiate, and instantiate any we can. RETRIES is the
23337 number of times we retry pending template instantiation. */
23339 void
23341 {
23345 /* Instantiating templates may trigger vtable generation. This in turn
23346 may require further template instantiations. We place a limit here
23347 to avoid infinite loop. */
23349 {
23353 "template instantiation depth exceeds maximum of %d"
23354 " instantiating %q+D, possibly from virtual table generation"
23358 /* Pretend that we defined it. */
23361 }
23363 do
23364 {
23369 {
23374 {
23376 {
23391 }
23394 }
23395 else
23396 {
23399 {
23400 instantiation
23406 }
23410 }
23413 /* If INSTANTIATION has been instantiated, then we don't
23414 need to consider it again in the future. */
23416 else
23417 {
23420 }
23423 }
23425 }
23429 }
23431 /* Substitute ARGVEC into T, which is a list of initializers for
23432 either base class or a non-static data member. The TREE_PURPOSEs
23433 are DECLs, and the TREE_VALUEs are the initializer values. Used by
23434 instantiate_decl. */
23436 static tree
23438 {
23442 {
23443 tree decl;
23444 tree init;
23450 {
23451 tree expr;
23452 tree arg;
23454 /* Expand the base class expansion type into separate base
23455 classes. */
23457 tf_warning_or_error,
23458 NULL_TREE);
23462 /* We'll be building separate TREE_LISTs of arguments for
23463 each base. */
23469 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
23470 expand each argument in the TREE_VALUE of t. */
23477 /* VOID_TYPE_NODE is used to indicate
23478 value-initialization. */
23479 {
23482 }
23483 else
23484 {
23485 /* Substitute parameter packs into each argument in the
23486 TREE_LIST. */
23489 {
23490 tree expanded_exprs;
23492 /* Expand the argument. */
23494 expanded_exprs
23496 tf_warning_or_error,
23497 NULL_TREE);
23501 /* Prepend each of the expanded expressions to the
23502 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
23504 {
23509 }
23510 }
23513 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
23514 since we built them backwards. */
23516 {
23519 }
23520 }
23521 }
23524 {
23526 {
23530 }
23531 else
23532 {
23533 tree tmp;
23548 /* If we had an initializer but it instantiated to nothing,
23549 value-initialize the object. This will only occur when
23550 the initializer was a pack expansion where the parameter
23551 packs used in that expansion were of length zero. */
23554 }
23557 {
23561 }
23562 }
23563 }
23565 }
23567 /* Set CURRENT_ACCESS_SPECIFIER based on the protection of DECL. */
23569 static void
23571 {
23576 else
23578 }
23580 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
23581 is the instantiation (which should have been created with
23582 start_enum) and ARGS are the template arguments to use. */
23584 static void
23586 {
23587 tree e;
23593 {
23594 tree value;
23595 tree decl;
23598 /* Note that in a template enum, the TREE_VALUE is the
23599 CONST_DECL, not the corresponding INTEGER_CST. */
23604 /* Give this enumeration constant the correct access. */
23607 /* Actually build the enumerator itself. Here we're assuming that
23608 enumerators can't have dependent attributes. */
23611 }
23621 }
23623 /* DECL is a FUNCTION_DECL that is a template specialization. Return
23624 its type -- but without substituting the innermost set of template
23625 arguments. So, innermost set of template parameters will appear in
23626 the type. */
23628 tree
23630 {
23631 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
23633 }
23635 /* Return truthvalue if we're processing a template different from
23636 the last one involved in diagnostics. */
23637 bool
23639 {
23641 }
23643 /* Remember current template involved in diagnostics. */
23644 void
23646 {
23648 }
23652 {
23654 }
23656 /* Return TRUE if current_function_decl is being instantiated, false
23657 otherwise. */
23659 bool
23661 {
23664 }
23666 /* [temp.param] Check that template non-type parm TYPE is of an allowable
23667 type. Return false for ok, true for disallowed. Issue error and
23668 inform messages under control of COMPLAIN. */
23670 static bool
23672 {
23687 /* A bound template template parm could later be instantiated to have a valid
23688 nontype parm type via an alias template. */
23694 {
23697 else
23699 type);
23700 }
23702 }
23704 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
23705 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
23707 static bool
23709 {
23710 tree scope;
23712 /* [temp.dep.type]
23714 A type is dependent if it is:
23716 -- a template parameter. Template template parameters are types
23717 for us (since TYPE_P holds true for them) so we handle
23718 them here. */
23722 /* -- a qualified-id with a nested-name-specifier which contains a
23723 class-name that names a dependent type or whose unqualified-id
23724 names a dependent type. */
23728 /* An alias template specialization can be dependent even if the
23729 resulting type is not. */
23733 /* -- a cv-qualified type where the cv-unqualified type is
23734 dependent.
23735 No code is necessary for this bullet; the code below handles
23736 cv-qualified types, and we don't want to strip aliases with
23737 TYPE_MAIN_VARIANT because of DR 1558. */
23738 /* -- a compound type constructed from any dependent type. */
23748 {
23749 tree arg_type;
23754 arg_type;
23759 /* A value-dependent noexcept-specifier makes the type dependent. */
23762 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
23763 affect overload resolution and treating it as dependent breaks
23764 things. */
23769 }
23770 /* -- an array type constructed from any dependent type or whose
23771 size is specified by a constant expression that is
23772 value-dependent.
23774 We checked for type- and value-dependence of the bounds in
23775 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
23777 {
23782 }
23784 /* -- a template-id in which either the template name is a template
23785 parameter ... */
23788 /* ... or any of the template arguments is a dependent type or
23789 an expression that is type-dependent or value-dependent. */
23791 && (any_dependent_template_arguments_p
23795 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and UNDERLYING_TYPEs are
23796 dependent; if the argument of the `typeof' expression is not
23797 type-dependent, then it should already been have resolved. */
23803 /* A template argument pack is dependent if any of its packed
23804 arguments are. */
23806 {
23812 }
23814 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
23815 be template parameters. */
23822 /* The standard does not specifically mention types that are local
23823 to template functions or local classes, but they should be
23824 considered dependent too. For example:
23826 template <int I> void f() {
23827 enum E { a = I };
23828 S<sizeof (E)> s;
23829 }
23831 The size of `E' cannot be known until the value of `I' has been
23832 determined. Therefore, `E' must be considered dependent. */
23836 /* Don't use type_dependent_expression_p here, as it can lead
23837 to infinite recursion trying to determine whether a lambda
23838 nested in a lambda is dependent (c++/47687). */
23842 && (any_dependent_template_arguments_p
23846 /* Other types are non-dependent. */
23848 }
23850 /* Returns TRUE if TYPE is dependent, in the sense of
23851 [temp.dep.type]. Note that a NULL type is considered dependent. */
23853 bool
23855 {
23856 /* If there are no template parameters in scope, then there can't be
23857 any dependent types. */
23859 {
23860 /* If we are not processing a template, then nobody should be
23861 providing us with a dependent type. */
23865 }
23867 /* If the type is NULL, we have not computed a type for the entity
23868 in question; in that case, the type is dependent. */
23872 /* Erroneous types can be considered non-dependent. */
23876 /* Getting here with global_type_node means we improperly called this
23877 function on the TREE_TYPE of an IDENTIFIER_NODE. */
23880 /* If we have not already computed the appropriate value for TYPE,
23881 do so now. */
23883 {
23886 }
23889 }
23891 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
23892 lookup. In other words, a dependent type that is not the current
23893 instantiation. */
23895 bool
23897 {
23900 }
23902 /* T is a SCOPE_REF; return whether we need to consider it
23903 instantiation-dependent so that we can check access at instantiation
23904 time even though we know which member it resolves to. */
23906 static bool
23908 {
23914 else
23916 }
23918 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
23919 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
23920 expression. */
23922 /* Note that this predicate is not appropriate for general expressions;
23923 only constant expressions (that satisfy potential_constant_expression)
23924 can be tested for value dependence. */
23926 bool
23928 {
23932 /* A type-dependent expression is also value-dependent. */
23937 {
23939 /* A dependent member function of the current instantiation. */
23943 /* A dependent member function of the current instantiation. */
23950 /* A name that has not been looked up -- must be dependent. */
23954 /* A non-type template parm. */
23958 /* A non-type template parm. */
23964 /* A constant with literal type and is initialized
23965 with an expression that is value-dependent. */
23967 /* FIXME cp_finish_decl doesn't fold reference initializers. */
23971 {
23975 }
23984 /* These expressions are value-dependent if the type to which
23985 the cast occurs is dependent or the expression being casted
23986 is value-dependent. */
23987 {
23993 /* A functional cast has a list of operands. */
23996 {
23997 /* If there are no operands, it must be an expression such
23998 as "int()". This should not happen for aggregate types
23999 because it would form non-constant expressions. */
24004 }
24010 }
24015 /* FALLTHRU */
24018 /* A `sizeof' expression is value-dependent if the operand is
24019 type-dependent or is a pack expansion. */
24028 /* An 'encode' expression is value-dependent if the operand is
24029 type-dependent. */
24038 /* All instantiation-dependent expressions should also be considered
24039 value-dependent. */
24047 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
24048 is value-dependent. */
24049 {
24058 }
24061 {
24078 }
24089 {
24093 }
24096 /* Treat all requires-expressions as value-dependent so
24097 we don't try to fold them. */
24104 {
24111 {
24113 /* In a call to a constexpr member function, look through the
24114 implicit ADDR_EXPR on the object argument so that it doesn't
24115 cause the call to be considered value-dependent. We also
24116 look through it in potential_constant_expression. */
24123 }
24125 }
24131 {
24133 tree val;
24140 }
24143 /* Treat a GNU statement expression as dependent to avoid crashing
24144 under instantiate_non_dependent_expr; it can't be constant. */
24148 /* A constant expression is value-dependent if any subexpression is
24149 value-dependent. */
24151 {
24158 {
24162 {
24165 /* In some cases, some of the operands may be missing.
24166 (For example, in the case of PREDECREMENT_EXPR, the
24167 amount to increment by may be missing.) That doesn't
24168 make the expression dependent. */
24171 }
24172 }
24176 }
24178 }
24180 /* The expression is not value-dependent. */
24182 }
24184 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
24185 [temp.dep.expr]. Note that an expression with no type is
24186 considered dependent. Other parts of the compiler arrange for an
24187 expression with type-dependent subexpressions to have no type, so
24188 this function doesn't have to be fully recursive. */
24190 bool
24192 {
24199 /* An unresolved name is always dependent. */
24205 /* A fold expression is type-dependent. */
24212 /* Some expression forms are never type-dependent. */
24226 /* The types of these expressions depends only on the type to which
24227 the cast occurs. */
24236 /* The types of these expressions depends only on the type created
24237 by the expression. */
24240 {
24241 /* For NEW_EXPR tree nodes created inside a template, either
24242 the object type itself or a TREE_LIST may appear as the
24243 operand 1. */
24246 /* This is an array type. We need to check array dimensions
24247 as well. */
24249 || value_dependent_expression_p
24251 else
24253 }
24256 {
24260 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
24261 contains an identifier associated by name lookup with one or more
24262 declarations declared with a dependent type, or...a
24263 nested-name-specifier or qualified-id that names a member of an
24264 unknown specialization. */
24267 }
24277 {
24278 tree elt;
24282 {
24285 }
24287 }
24289 /* A static data member of the current instantiation with incomplete
24290 array type is type-dependent, as the definition and specializations
24291 can have different bounds. */
24298 /* An array of unknown bound depending on a variadic parameter, eg:
24300 template<typename... Args>
24301 void foo (Args... args)
24302 {
24303 int arr[] = { args... };
24304 }
24306 template<int... vals>
24307 void bar ()
24308 {
24309 int arr[] = { vals... };
24310 }
24312 If the array has no length and has an initializer, it must be that
24313 we couldn't determine its length in cp_complete_array_type because
24314 it is dependent. */
24322 /* A function or variable template-id is type-dependent if it has any
24323 dependent template arguments. */
24327 {
24328 /* Consider the innermost template arguments, since those are the ones
24329 that come from the template-id; the template arguments for the
24330 enclosing class do not make it type-dependent unless they are used in
24331 the type of the decl. */
24333 && (any_dependent_template_arguments_p
24336 }
24338 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
24339 type-dependent. Checking this is important for functions with auto return
24340 type, which looks like a dependent type. */
24348 {
24352 }
24354 /* Always dependent, on the number of arguments if nothing else. */
24359 {
24364 {
24370 }
24371 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
24376 {
24381 }
24384 {
24391 }
24401 }
24405 /* Dependent type attributes might not have made it from the decl to
24406 the type yet. */
24412 }
24414 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
24415 type-dependent if the expression refers to a member of the current
24416 instantiation and the type of the referenced member is dependent, or the
24417 class member access expression refers to a member of an unknown
24418 specialization.
24420 This function returns true if the OBJECT in such a class member access
24421 expression is of an unknown specialization. */
24423 bool
24425 {
24426 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
24427 dependent. */
24432 }
24434 /* walk_tree callback function for instantiation_dependent_expression_p,
24435 below. Returns non-zero if a dependent subexpression is found. */
24437 static tree
24440 {
24442 {
24443 /* We don't have to worry about decltype currently because decltype
24444 of an instantiation-dependent expr is a dependent type. This
24445 might change depending on the resolution of DR 1172. */
24448 }
24451 {
24452 /* Don't treat an argument list as dependent just because it has no
24453 TREE_TYPE. */
24461 /* Handle expressions with type operands. */
24466 {
24471 {
24474 else
24475 {
24478 }
24479 }
24481 }
24485 /* In a template, finish_class_member_access_expr creates a
24486 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
24487 type-dependent, so that we can check access control at
24488 instantiation time (PR 42277). See also Core issue 1273. */
24495 else
24498 /* Treat statement-expressions as dependent. */
24502 /* Treat requires-expressions as dependent. */
24507 /* Treat calls to function concepts as dependent. */
24513 /* And variable concepts. */
24520 }
24524 else
24526 }
24528 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
24529 sense defined by the ABI:
24531 "An expression is instantiation-dependent if it is type-dependent
24532 or value-dependent, or it has a subexpression that is type-dependent
24533 or value-dependent."
24535 Except don't actually check value-dependence for unevaluated expressions,
24536 because in sizeof(i) we don't care about the value of i. Checking
24537 type-dependence will in turn check value-dependence of array bounds/template
24538 arguments as needed. */
24540 bool
24542 {
24543 tree result;
24554 }
24556 /* As above, but also check value-dependence of the expression as a whole. */
24558 bool
24560 {
24563 }
24565 /* Like type_dependent_expression_p, but it also works while not processing
24566 a template definition, i.e. during substitution or mangling. */
24568 bool
24570 {
24576 }
24578 /* Returns TRUE if ARGS contains a type-dependent expression. */
24580 bool
24582 {
24584 tree arg;
24587 {
24590 }
24592 }
24594 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24595 expressions) contains any type-dependent expressions. */
24597 bool
24599 {
24605 }
24607 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
24608 expressions) contains any value-dependent expressions. */
24610 bool
24612 {
24618 }
24620 /* Returns TRUE if the ARG (a template argument) is dependent. */
24622 bool
24624 {
24628 /* Assume a template argument that was wrongly written by the user
24629 is dependent. This is consistent with what
24630 any_dependent_template_arguments_p [that calls this function]
24631 does. */
24641 {
24644 /* A member template of a dependent class is not necessarily
24645 type-dependent, but it is a dependent template argument because it
24646 will be a member of an unknown specialization to that template. */
24649 }
24651 {
24655 {
24658 }
24661 }
24664 else
24667 }
24669 /* Returns true if ARGS (a collection of template arguments) contains
24670 any types that require structural equality testing. */
24672 bool
24674 {
24684 {
24687 {
24693 {
24694 /* Look inside the argument pack. */
24697 }
24700 {
24713 }
24714 }
24715 }
24718 }
24720 /* Returns true if ARGS (a collection of template arguments) contains
24721 any dependent arguments. */
24723 bool
24725 {
24735 {
24740 }
24743 }
24745 /* Returns TRUE if the template TMPL is type-dependent. */
24747 bool
24749 {
24751 {
24756 }
24758 /* Template template parameters are dependent. */
24762 /* So are names that have not been looked up. */
24766 }
24768 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
24770 bool
24772 {
24775 }
24777 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
24778 are dependent. */
24780 bool
24782 {
24789 {
24811 {
24815 }
24819 {
24823 {
24828 }
24829 }
24830 }
24833 }
24835 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
24836 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
24837 no such TYPE can be found. Note that this function peers inside
24838 uninstantiated templates and therefore should be used only in
24839 extremely limited situations. ONLY_CURRENT_P restricts this
24840 peering to the currently open classes hierarchy (which is required
24841 when comparing types). */
24843 tree
24845 {
24846 tree scope;
24847 tree name;
24848 tree decl;
24850 tree pushed_scope;
24851 tree result;
24856 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
24857 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of
24858 a TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL representing
24859 the typedef. In that case TYPE_IDENTIFIER (type) is not the non-qualified
24860 identifier of the TYPENAME_TYPE anymore.
24861 So by getting the TYPE_IDENTIFIER of the _main declaration_ of the
24862 TYPENAME_TYPE instead, we avoid messing up with a possible
24863 typedef variant case. */
24866 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
24867 it first before we can figure out what NAME refers to. */
24869 {
24871 /* Given a class template A with a dependent base with nested type C,
24872 typedef typename A::C::C C will land us here, as trying to resolve
24873 the initial A::C leads to the local C typedef, which leads back to
24874 A::C::C. So we break the recursion now. */
24876 else
24878 }
24879 /* If we don't know what SCOPE refers to, then we cannot resolve the
24880 TYPENAME_TYPE. */
24883 /* If this is a typedef, we don't want to look inside (c++/11987). */
24886 /* If SCOPE isn't the template itself, it will not have a valid
24887 TYPE_FIELDS list. */
24889 /* scope is either the template itself or a compatible instantiation
24890 like X<T>, so look up the name in the original template. */
24892 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
24894 /* If scope has no fields, it can't be a current instantiation. Check this
24895 before currently_open_class to avoid infinite recursion (71515). */
24898 /* If the SCOPE is not the current instantiation, there's no reason
24899 to look inside it. */
24902 /* Enter the SCOPE so that name lookup will be resolved as if we
24903 were in the class definition. In particular, SCOPE will no
24904 longer be considered a dependent type. */
24906 /* Look up the declaration. */
24908 tf_warning_or_error);
24912 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
24913 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
24919 {
24923 }
24926 {
24927 /* Obtain the template and the arguments. */
24930 {
24931 /* We get here with a plain identifier because a previous tentative
24932 parse of the nested-name-specifier as part of a ptr-operator saw
24933 ::template X<A>. The use of ::template is necessary in a
24934 ptr-operator, but wrong in a declarator-id.
24936 [temp.names]: In a qualified-id of a declarator-id, the keyword
24937 template shall not appear at the top level. */
24941 }
24943 /* Instantiate the template. */
24949 }
24951 /* Leave the SCOPE. */
24955 /* If we failed to resolve it, return the original typename. */
24959 /* If lookup found a typename type, resolve that too. */
24961 {
24962 /* Ill-formed programs can cause infinite recursion here, so we
24963 must catch that. */
24967 }
24969 /* Qualify the resulting type. */
24975 }
24977 /* EXPR is an expression which is not type-dependent. Return a proxy
24978 for EXPR that can be used to compute the types of larger
24979 expressions containing EXPR. */
24981 tree
24983 {
24984 tree inner_expr;
24986 /* When checking, try to get a constant value for all non-dependent
24987 expressions in order to expose bugs in *_dependent_expression_p
24988 and constexpr. This can affect code generation, see PR70704, so
24989 only do this for -fchecking=2. */
24992 /* Don't do this during nsdmi parsing as it can lead to
24993 unexpected recursive instantiations. */
24995 /* Don't do this during concept expansion either and for
24996 the same reason. */
25000 /* Preserve OVERLOADs; the functions must be available to resolve
25001 types. */
25012 /* There is no need to return a proxy for a variable. */
25015 /* Preserve string constants; conversions from string constants to
25016 "char *" are allowed, even though normally a "const char *"
25017 cannot be used to initialize a "char *". */
25020 /* Preserve void and arithmetic constants, as an optimization -- there is no
25021 reason to create a new node. */
25026 /* Preserve THROW_EXPRs -- all throw-expressions have type "void".
25027 There is at least one place where we want to know that a
25028 particular expression is a throw-expression: when checking a ?:
25029 expression, there are special rules if the second or third
25030 argument is a throw-expression. */
25034 /* Don't wrap an initializer list, we need to be able to look inside. */
25038 /* Don't wrap a dummy object, we need to be able to test for it. */
25057 /* If the type is unknown, it can't really be non-dependent */
25060 /* Otherwise, build a NON_DEPENDENT_EXPR. */
25062 }
25064 /* ARGS is a vector of expressions as arguments to a function call.
25065 Replace the arguments with equivalent non-dependent expressions.
25066 This modifies ARGS in place. */
25068 void
25070 {
25072 tree arg;
25075 {
25079 }
25080 }
25082 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
25083 TEMPLATE_TYPE_PARM with a level one deeper than the actual template
25084 parms. If set_canonical is true, we set TYPE_CANONICAL on it. */
25086 static tree
25088 {
25102 }
25104 tree
25106 {
25108 }
25110 tree
25112 {
25114 }
25116 /* Return a C++17 deduction placeholder for class template TMPL. */
25118 tree
25120 {
25124 }
25126 /* True iff T is a C++17 class template deduction placeholder. */
25128 bool
25130 {
25132 }
25134 /* Make a "constrained auto" type-specifier. This is an
25135 auto type with constraints that must be associated after
25136 deduction. The constraint is formed from the given
25137 CONC and its optional sequence of arguments, which are
25138 non-null if written as partial-concept-id. */
25140 tree
25142 {
25145 /* Build the constraint. */
25153 /* Our canonical type depends on the constraint. */
25156 /* Attach the constraint to the type declaration. */
25159 }
25161 /* Given type ARG, return std::initializer_list<ARG>. */
25163 static tree
25165 {
25169 {
25173 "deducing from brace-enclosed initializer list"
25177 }
25183 }
25185 /* Replace auto in TYPE with std::initializer_list<auto>. */
25187 static tree
25189 {
25196 }
25198 /* Hash traits for hashing possibly constrained 'auto'
25199 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
25202 {
25205 };
25207 /* Hash the 'auto' T. */
25209 inline hashval_t
25211 {
25213 /* Matching constrained-type-specifiers denote the same template
25214 parameter, so hash the constraint. */
25216 else
25217 /* But unconstrained autos are all separate, so just hash the pointer. */
25219 }
25221 /* Compare two 'auto's. */
25225 {
25232 /* Two unconstrained autos are distinct. */
25237 }
25239 /* for_each_template_parm callback for extract_autos: if t is a (possibly
25240 constrained) auto, add it to the vector. */
25242 static int
25244 {
25247 {
25248 /* All the autos were built with index 0; fix that up now. */
25252 /* If this is a repeated constrained-type-specifier, use the index we
25253 chose before. */
25255 else
25256 {
25257 /* Otherwise this is new, so use the current count. */
25260 }
25262 }
25264 /* Always keep walking. */
25266 }
25268 /* Return a TREE_VEC of the 'auto's used in type under the Concepts TS, which
25269 says they can appear anywhere in the type. */
25271 static tree
25273 {
25282 {
25287 }
25290 }
25292 /* The stem for deduction guide names. */
25295 /* Return the name for a deduction guide for class template TMPL. */
25297 tree
25299 {
25310 }
25312 /* True if NAME is the name of a deduction guide. */
25314 bool
25316 {
25320 }
25322 /* True if FN is a deduction guide. */
25324 bool
25326 {
25331 }
25333 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
25335 bool
25337 {
25344 }
25346 /* True if FN is a guide generated from a constructor template. */
25348 bool
25350 {
25358 }
25360 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
25361 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
25362 template parameter types. Note that the handling of template template
25363 parameters relies on current_template_parms being set appropriately for the
25364 new template. */
25366 static tree
25369 {
25372 tree newtype;
25375 {
25382 }
25383 else
25387 tree newdecl
25392 tree newidx;
25395 {
25405 {
25410 // First create a copy (ttargs) of tsubst_args with an
25411 // additional level for the template template parameter's own
25412 // template parameters (ttparms).
25413 tree ttparms = (INNERMOST_TEMPLATE_PARMS
25421 // Substitute ttargs into ttparms to fix references to
25422 // other template parameters.
25424 complain);
25425 // Now substitute again with args based on tparms, to reduce
25426 // the level of the ttparms.
25429 complain);
25430 // Finally, tack the adjusted parms onto tparms.
25432 current_template_parms);
25434 }
25435 }
25436 else
25437 {
25439 tree newconst
25451 }
25454 }
25456 /* Returns a C++17 class deduction guide template based on the constructor
25457 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
25458 guide, or REFERENCE_TYPE for an implicit copy/move guide. */
25460 static tree
25462 {
25466 location_t loc;
25470 {
25474 {
25477 }
25478 else
25488 }
25489 else
25490 {
25493 fn_tmpl
25503 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
25504 fully specialized args for the enclosing class. Strip those off, as
25505 the deduction guide won't have those template parameters. */
25508 /* Discard the 'this' parameter. */
25516 {
25519 /* For a member template constructor, we need to flatten the two
25520 template parameter lists into one, and then adjust the function
25521 signature accordingly. This gets...complicated. */
25524 /* For a member template we should have two levels of parms/args, one
25525 for the class and one for the constructor. We stripped
25526 specialized args for further enclosing classes above. */
25530 /* Template args for translating references to the two-level template
25531 parameters into references to the one-level template parameters we
25532 are creating. */
25537 /* Template parms for the constructor template. */
25540 /* Template parms for the class template. */
25544 /* Template parms for the deduction guide start as a copy of the
25545 template parms for the class. We set current_template_parms for
25546 lookup_template_class_1. */
25552 /* Now we need to rewrite the constructor parms to append them to the
25553 class parms. */
25555 {
25570 }
25572 /* Now we have a final set of template parms to substitute into the
25573 function signature. */
25582 }
25584 }
25587 {
25588 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
25592 }
25596 FUNCTION_DECL,
25613 }
25615 /* Deduce template arguments for the class template placeholder PTYPE for
25616 template TMPL based on the initializer INIT, and return the resulting
25617 type. */
25619 static tree
25621 tsubst_flags_t complain)
25622 {
25624 {
25625 /* We should have handled this in the caller. */
25631 }
25642 {
25645 {
25646 /* As an exception, the first phase in 16.3.1.7 (considering the
25647 initializer list as a single argument) is omitted if the
25648 initializer list consists of a single expression of type cv U,
25649 where U is a specialization of C or a class derived from a
25650 specialization of C. */
25661 }
25664 else
25666 }
25667 else
25678 /* Prune explicit deduction guides in copy-initialization context. */
25680 {
25686 {
25687 /* Found a nonconverting guide, prune the candidates. */
25694 }
25695 }
25700 {
25703 }
25706 // FIXME cache artificial deduction guides
25708 {
25713 else
25717 }
25721 /* If this is list-initialization and the class has a list constructor, first
25722 try deducing from the list as a single argument, as [over.match.list]. */
25726 {
25730 }
25732 {
25738 {
25739 /* That didn't work, now try treating the list as a sequence of
25740 arguments. */
25743 }
25744 }
25746 /* Maybe generate an implicit deduction guide. */
25748 {
25752 /* Generate a copy guide. */
25755 /* Generate a default guide. */
25759 {
25762 }
25763 }
25766 {
25768 " of %qT, as it has no non-explicit deduction guides or "
25771 }
25773 {
25777 }
25780 {
25784 }
25787 {
25797 }
25802 }
25804 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25805 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE. */
25807 tree
25809 {
25811 tf_warning_or_error,
25812 adc_unspecified);
25813 }
25815 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
25816 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
25817 The CONTEXT determines the context in which auto deduction is performed
25818 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
25819 OUTER_TARGS are used during template argument deduction
25820 (context == adc_unify) to properly substitute the result, and is ignored
25821 in other contexts.
25823 For partial-concept-ids, extra args may be appended to the list of deduced
25824 template arguments prior to determining constraint satisfaction. */
25826 tree
25830 {
25831 tree targs;
25838 /* Defining a subset of type-dependent expressions that we can deduce
25839 from ahead of time isn't worth the trouble. */
25843 /* C++17 class template argument deduction. */
25847 /* Nothing we can do with this, even in deduction context. */
25850 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
25851 with either a new invented type template parameter U or, if the
25852 initializer is a braced-init-list (8.5.4), with
25853 std::initializer_list<U>. */
25855 {
25860 else
25861 {
25863 {
25867 "for deduction to %<std::initializer_list%>, use copy-"
25869 }
25871 }
25872 }
25883 /* [dcl.decomp]/1 - if decomposition declaration has no ref-qualifiers
25884 and initializer has array type, deduce cv-qualified array type. */
25886 complain);
25888 {
25897 {
25901 }
25902 }
25903 else
25904 {
25906 tree tparms;
25910 else
25911 {
25915 }
25922 {
25924 /* Try again at instantiation time. */
25928 /* If type is error_mark_node a diagnostic must have been
25929 emitted by now. Also, having a mention to '<type error>'
25930 in the diagnostic is not really useful to the user. */
25931 {
25935 else
25940 }
25942 }
25943 }
25945 /* Check any placeholder constraints against the deduced type. */
25948 {
25949 /* Use the deduced type to check the associated constraints. If we
25950 have a partial-concept-id, rebuild the argument list so that
25951 we check using the extra arguments. */
25955 {
25958 }
25959 else
25962 {
25964 {
25966 {
25984 }
25986 }
25988 }
25989 }
25995 }
25997 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
25998 result. */
26000 tree
26002 {
26004 {
26010 /* In an abbreviated function template we didn't know we were dealing
26011 with a function template when we saw the auto return type, so update
26012 it to have the correct level. */
26014 }
26016 }
26018 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
26019 'decltype(auto)' or a deduced class template. */
26021 bool
26023 {
26029 else
26031 }
26033 /* for_each_template_parm callback for type_uses_auto. */
26035 int
26037 {
26039 }
26041 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
26042 a use of `auto'. Returns NULL_TREE otherwise. */
26044 tree
26046 {
26050 {
26051 /* The Concepts TS allows multiple autos in one type-specifier; just
26052 return the first one we find, do_auto_deduction will collect all of
26053 them. */
26057 else
26059 }
26060 else
26062 }
26064 /* For a given template T, return the vector of typedefs referenced
26065 in T for which access check is needed at T instantiation time.
26066 T is either a FUNCTION_DECL or a RECORD_TYPE.
26067 Those typedefs were added to T by the function
26068 append_type_to_template_for_access_check. */
26072 {
26073 tree ti;
26084 {
26089 }
26092 }
26094 /* Append the typedef TYPE_DECL used in template T to a list of typedefs
26095 tied to T. That list of typedefs will be access checked at
26096 T instantiation time.
26097 T is either a FUNCTION_DECL or a RECORD_TYPE.
26098 TYPE_DECL is a TYPE_DECL node representing a typedef.
26099 SCOPE is the scope through which TYPE_DECL is accessed.
26100 LOCATION is the location of the usage point of TYPE_DECL.
26102 This function is a subroutine of
26103 append_type_to_template_for_access_check. */
26105 static void
26107 tree type_decl,
26108 tree scope,
26109 location_t location)
26110 {
26111 qualified_typedef_usage_t typedef_usage;
26112 tree ti;
26119 && type_decl
26133 }
26135 /* Append TYPE_DECL to the template TEMPL.
26136 TEMPL is either a class type, a FUNCTION_DECL or a a TEMPLATE_DECL.
26137 At TEMPL instanciation time, TYPE_DECL will be checked to see
26138 if it can be accessed through SCOPE.
26139 LOCATION is the location of the usage point of TYPE_DECL.
26141 e.g. consider the following code snippet:
26143 class C
26144 {
26145 typedef int myint;
26146 };
26148 template<class U> struct S
26149 {
26150 C::myint mi; // <-- usage point of the typedef C::myint
26151 };
26153 S<char> s;
26155 At S<char> instantiation time, we need to check the access of C::myint
26156 In other words, we need to check the access of the myint typedef through
26157 the C scope. For that purpose, this function will add the myint typedef
26158 and the scope C through which its being accessed to a list of typedefs
26159 tied to the template S. That list will be walked at template instantiation
26160 time and access check performed on each typedefs it contains.
26161 Note that this particular code snippet should yield an error because
26162 myint is private to C. */
26164 void
26166 tree type_decl,
26167 tree scope,
26168 location_t location)
26169 {
26175 /* Make sure we don't append the type to the template twice. */
26182 }
26184 /* Convert the generic type parameters in PARM that match the types given in the
26185 range [START_IDX, END_IDX) from the current_template_parms into generic type
26186 packs. */
26188 tree
26190 {
26201 {
26202 /* Create a distinct parameter pack type from the current parm and add it
26203 to the replacement args to tsubst below into the generic function
26204 parameter. */
26219 }
26225 /* If there are more levels then build up the replacement with the outer
26226 template parms. */
26230 replacement);
26233 }
26235 /* Entries in the decl_constraint hash table. */
26237 {
26238 tree decl;
26239 tree ci;
26240 };
26242 /* Hashing function and equality for constraint entries. */
26244 {
26246 {
26248 }
26251 {
26253 }
26254 };
26256 /* A mapping from declarations to constraint information. Note that
26257 both templates and their underlying declarations are mapped to the
26258 same constraint information.
26260 FIXME: This is defined in pt.c because garbage collection
26261 code is not being generated for constraint.cc. */
26265 /* Returns the template constraints of declaration T. If T is not
26266 constrained, return NULL_TREE. Note that T must be non-null. */
26268 tree
26270 {
26281 else
26283 }
26285 /* Associate the given constraint information CI with the declaration
26286 T. If T is a template, then the constraints are associated with
26287 its underlying declaration. Don't build associations if CI is
26288 NULL_TREE. */
26290 void
26292 {
26304 }
26306 /* Remove the associated constraints of the declaration T. */
26308 void
26310 {
26319 }
26321 /* Memoized satisfaction results for declarations. This
26322 maps the pair (constraint_info, arguments) to the result computed
26323 by constraints_satisfied_p. */
26326 {
26327 tree ci;
26328 tree args;
26329 tree result;
26330 };
26332 /* Hashing function and equality for constraint entries. */
26335 {
26337 {
26340 }
26343 {
26345 }
26346 };
26348 /* Memoized satisfaction results for concept checks. */
26351 {
26352 tree tmpl;
26353 tree args;
26354 tree result;
26355 };
26357 /* Hashing function and equality for constraint entries. */
26360 {
26362 {
26364 }
26367 {
26372 }
26373 };
26378 /* Search for a memoized satisfaction result. Returns one of the
26379 truth value nodes if previously memoized, or NULL_TREE otherwise. */
26381 tree
26383 {
26388 else
26390 }
26392 /* Memoize the result of a satisfication test. Returns the saved result. */
26394 tree
26396 {
26403 }
26405 /* Search for a memoized satisfaction result for a concept. */
26407 tree
26409 {
26414 else
26416 }
26418 /* Memoize the result of a concept check. Returns the saved result. */
26420 tree
26422 {
26429 }
26433 /* Returns a prior concept specialization. This returns the substituted
26434 and normalized constraints defined by the concept. */
26436 tree
26438 {
26443 else
26445 }
26447 /* Save a concept expansion for later. */
26449 tree
26451 {
26458 }
26460 static hashval_t
26462 {
26471 }
26473 /* Compare the constraints of two subsumption entries. The LEFT1 and
26474 LEFT2 arguments comprise the first subsumption pair and the RIGHT1
26475 and RIGHT2 arguments comprise the second. These are all CHECK_CONSTRs. */
26477 static bool
26479 {
26487 }
26489 /* Key/value pair for learning and memoizing subsumption results. This
26490 associates a pair of check constraints (including arguments) with
26491 a boolean value indicating the result. */
26494 {
26495 tree t1;
26496 tree t2;
26498 };
26500 /* Hashing function and equality for constraint entries. */
26503 {
26505 {
26507 }
26510 {
26515 }
26516 };
26520 /* Search for a previously cached subsumption result. */
26524 {
26529 else
26531 }
26533 /* Save a subsumption result. */
26535 bool
26537 {
26544 }
26546 /* Set up the hash table for constraint association. */
26548 void
26550 {
26559 }
26561 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
26562 0..N-1. */
26564 void
26566 {
26569 integer_type_node,
26570 NULL_TREE),
26574 }
26576 /* Set up the hash tables for template instantiations. */
26578 void
26580 {
26586 }
26588 /* Print stats about the template hash tables for -fstats. */
26590 void
26592 {
26601 }